b8b11599dd 
								
							 
						 
						
							
							
								
								Fix SimplifyCFG/2006-10-19-UncondDiv.ll by disabling a bad xform.  
							
							... 
							
							
							
							llvm-svn: 31061 
							
						 
						
							2006-10-20 00:42:07 +00:00  
				
					
						
							
							
								 
						
							
								c9009d917d 
								
							 
						 
						
							
							
								
								Fix PR867 (and maybe 868) and testcsae:  
							
							... 
							
							
							
							Transforms/SimplifyCFG/2006-08-03-Crash.ll
llvm-svn: 29515 
							
						 
						
							2006-08-03 21:40:24 +00:00  
				
					
						
							
							
								 
						
							
								b5c9d7a0af 
								
							 
						 
						
							
							
								
								Fix an infinite loop on Transforms/SimplifyCFG/2006-06-12-InfLoop.ll  
							
							... 
							
							
							
							llvm-svn: 28758 
							
						 
						
							2006-06-12 20:18:01 +00:00  
				
					
						
							
							
								 
						
							
								35515557c7 
								
							 
						 
						
							
							
								
								remove some dead code identified by coverity  
							
							... 
							
							
							
							llvm-svn: 28289 
							
						 
						
							2006-05-14 18:45:44 +00:00  
				
					
						
							
							
								 
						
							
								3237da073e 
								
							 
						 
						
							
							
								
								remove dead variables  
							
							... 
							
							
							
							llvm-svn: 28286 
							
						 
						
							2006-05-14 18:33:57 +00:00  
				
					
						
							
							
								 
						
							
								d95665188b 
								
							 
						 
						
							
							
								
								Fix Transforms/SimplifyCFG/2006-02-17-InfiniteUnroll.ll  
							
							... 
							
							
							
							llvm-svn: 26275 
							
						 
						
							2006-02-18 00:33:17 +00:00  
				
					
						
							
							
								 
						
							
								469640e506 
								
							 
						 
						
							
							
								
								Add explicit #includes of <iostream>  
							
							... 
							
							
							
							llvm-svn: 25509 
							
						 
						
							2006-01-22 22:53:01 +00:00  
				
					
						
							
							
								 
						
							
								2820b8c855 
								
							 
						 
						
							
							
								
								Fix SimplifyCFG/2005-12-03-IncorrectPHIFold.ll  
							
							... 
							
							
							
							llvm-svn: 24581 
							
						 
						
							2005-12-03 18:25:58 +00:00  
				
					
						
							
							
								 
						
							
								4c3b2b536c 
								
							 
						 
						
							
							
								
								Clean up the code a bit.  Use isInstructionTriviallyDead to be more aggressive  
							
							... 
							
							
							
							and more correct than use_empty().  This fixes PR635 and
SimplifyCFG/2005-10-02-InvokeSimplify.ll
llvm-svn: 23616 
							
						 
						
							2005-10-03 23:43:43 +00:00  
				
					
						
							
							
								 
						
							
								499e33646e 
								
							 
						 
						
							
							
								
								remove some debugging code  
							
							... 
							
							
							
							llvm-svn: 23411 
							
						 
						
							2005-09-23 18:49:09 +00:00  
				
					
						
							
							
								 
						
							
								c59a371d45 
								
							 
						 
						
							
							
								
								Fold two consequtive branches that share a common destination between them.  
							
							... 
							
							
							
							This implements SimplifyCFG/branch-fold.ll, and is useful on ?:/min/max heavy
code
llvm-svn: 23410 
							
						 
						
							2005-09-23 18:47:20 +00:00  
				
					
						
							
							
								 
						
							
								3a978bf66d 
								
							 
						 
						
							
							
								
								simplify some logic further  
							
							... 
							
							
							
							llvm-svn: 23408 
							
						 
						
							2005-09-23 07:23:18 +00:00  
				
					
						
							
							
								 
						
							
								cc14ebc17b 
								
							 
						 
						
							
							
								
								pull a bunch of logic out of SimplifyCFG into a helper fn  
							
							... 
							
							
							
							llvm-svn: 23407 
							
						 
						
							2005-09-23 06:39:30 +00:00  
				
					
						
							
							
								 
						
							
								6c70106053 
								
							 
						 
						
							
							
								
								Start threading across blocks with code in them, so long as the code does  
							
							... 
							
							
							
							not define a value that is used outside of it's block.  This catches many
more simplifications, e.g. 854 in 176.gcc, 137 in vpr, etc.
This implements branch-phi-thread.ll:test3.ll
llvm-svn: 23397 
							
						 
						
							2005-09-20 01:48:40 +00:00  
				
					
						
							
							
								 
						
							
								f0bd8d0107 
								
							 
						 
						
							
							
								
								Implement merging of blocks with the same condition if the block has multiple  
							
							... 
							
							
							
							predecessors.  This implements branch-phi-thread.ll::test1
llvm-svn: 23395 
							
						 
						
							2005-09-20 00:43:16 +00:00  
				
					
						
							
							
								 
						
							
								049cb4482f 
								
							 
						 
						
							
							
								
								Reject a case we don't handle yet  
							
							... 
							
							
							
							llvm-svn: 23393 
							
						 
						
							2005-09-19 23:57:04 +00:00  
				
					
						
							
							
								 
						
							
								a160924d57 
								
							 
						 
						
							
							
								
								remove debugging code :-/  
							
							... 
							
							
							
							llvm-svn: 23392 
							
						 
						
							2005-09-19 23:50:15 +00:00  
				
					
						
							
							
								 
						
							
								748f903046 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/branch-phi-thread.ll, the most trivial case of threading  
							
							... 
							
							
							
							control across branches with determined outcomes.  More generality to follow.
This triggers a couple thousand times in specint.
llvm-svn: 23391 
							
						 
						
							2005-09-19 23:49:37 +00:00  
				
					
						
							
							
								 
						
							
								d683bdd0f8 
								
							 
						 
						
							
							
								
								Fix Transforms/SimplifyCFG/2005-08-03-PHIFactorCrash.ll, a problem that  
							
							... 
							
							
							
							occurred while bugpointing another testcase
llvm-svn: 22621 
							
						 
						
							2005-08-03 17:59:45 +00:00  
				
					
						
							
							
								 
						
							
								2dbf1960ff 
								
							 
						 
						
							
							
								
								Finally, add the required constraint checks to fix  Transforms/SimplifyCFG/2005-08-01-PHIUpdateFail.ll  
							
							... 
							
							
							
							the right way
llvm-svn: 22615 
							
						 
						
							2005-08-03 00:59:12 +00:00  
				
					
						
							
							
								 
						
							
								908036942c 
								
							 
						 
						
							
							
								
								Simplify some code, add the correct pred checks  
							
							... 
							
							
							
							llvm-svn: 22613 
							
						 
						
							2005-08-03 00:38:27 +00:00  
				
					
						
							
							
								 
						
							
								982b75c061 
								
							 
						 
						
							
							
								
								Refactor code out of PropagatePredecessorsForPHIs, turning it into a pure function with no side-effects  
							
							... 
							
							
							
							llvm-svn: 22612 
							
						 
						
							2005-08-03 00:29:26 +00:00  
				
					
						
							
							
								 
						
							
								1f047fd513 
								
							 
						 
						
							
							
								
								use splice instead of remove/insert to avoid some symtab operations  
							
							... 
							
							
							
							llvm-svn: 22611 
							
						 
						
							2005-08-03 00:23:42 +00:00  
				
					
						
							
							
								 
						
							
								76dc204488 
								
							 
						 
						
							
							
								
								move two functions up in the file, use SafeToMergeTerminators to eliminate  
							
							... 
							
							
							
							some duplicated code
llvm-svn: 22610 
							
						 
						
							2005-08-03 00:19:45 +00:00  
				
					
						
							
							
								 
						
							
								733d6704ce 
								
							 
						 
						
							
							
								
								Rip some code out of the main SimplifyCFG function into a subfunction and  
							
							... 
							
							
							
							call it from the only place it is live.  No functionality changes.
llvm-svn: 22609 
							
						 
						
							2005-08-03 00:11:16 +00:00  
				
					
						
							
							
								 
						
							
								ac594de8dc 
								
							 
						 
						
							
							
								
								Disable this patch:  
							
							... 
							
							
							
							http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20050801/027345.html 
This breaks real programs and only fixes an obscure regression testcase.  A
real fix is in development.
llvm-svn: 22606 
						
							2005-08-02 23:31:38 +00:00  
				
					
						
							
							
								 
						
							
								eee90f7eb4 
								
							 
						 
						
							
							
								
								Change a place to use an arbitrary value instead of null, when possible  
							
							... 
							
							
							
							llvm-svn: 22605 
							
						 
						
							2005-08-02 23:29:23 +00:00  
				
					
						
							
							
								 
						
							
								4fd3e16cbd 
								
							 
						 
						
							
							
								
								This code was very close, but not quite right.  It did not take into  
							
							... 
							
							
							
							consideration the case where a reference in an unreachable block could
occur.  This fixes Transforms/SimplifyCFG/2005-08-01-PHIUpdateFail.ll,
something I ran into while bugpoint'ing another pass.
llvm-svn: 22584 
							
						 
						
							2005-08-02 03:24:05 +00:00  
				
					
						
							
							
								 
						
							
								5e735294bf 
								
							 
						 
						
							
							
								
								Don't crash on:  X = phi (X, X).  
							
							... 
							
							
							
							This fixes PR584 and Transforms/SimplifyCFG/2005-06-16-PHICrash.ll
llvm-svn: 22232 
							
						 
						
							2005-06-17 01:45:53 +00:00  
				
					
						
							
							
								 
						
							
								19f9f32a5c 
								
							 
						 
						
							
							
								
								Fix Transforms/SimplifyCFG/switch-simplify-crash.ll  
							
							... 
							
							
							
							llvm-svn: 22158 
							
						 
						
							2005-05-20 22:19:54 +00:00  
				
					
						
							
							
								 
						
							
								bcefcf8552 
								
							 
						 
						
							
							
								
								Make sure to preserve the calling convention when changing an invoke into  
							
							... 
							
							
							
							a call.  This fixes Prolangs-C++/deriv2, kimwitu++, and Misc-C++/bigfib
on X86 with -enable-x86-fastcc.
llvm-svn: 22023 
							
						 
						
							2005-05-14 12:21:56 +00:00  
				
					
						
							
							
								 
						
							
								b1c9317bb4 
								
							 
						 
						
							
							
								
								Remove trailing whitespace  
							
							... 
							
							
							
							llvm-svn: 21427 
							
						 
						
							2005-04-21 23:48:37 +00:00  
				
					
						
							
							
								 
						
							
								b38b443b15 
								
							 
						 
						
							
							
								
								Teach simplifycfg that setcc is cheap and non-trapping, so that it can  
							
							... 
							
							
							
							convert this:
        %tmp.1 = seteq int %i, 0                ; <bool> [#uses=1]
        br bool %tmp.1, label %shortcirc_done, label %shortcirc_next
shortcirc_next:         ; preds = %entry
        %tmp.4 = seteq int %j, 0                ; <bool> [#uses=1]
        br label %shortcirc_done
shortcirc_done:         ; preds = %shortcirc_next, %entry
        %shortcirc_val = phi bool [ %tmp.4, %shortcirc_next ], [ true, %entry ]         ; <bool> [#uses=1]
to this:
        %tmp.1 = seteq int %i, 0                ; <bool> [#uses=1]
        %tmp.4 = seteq int %j, 0                ; <bool> [#uses=1]
        %shortcirc_val = select bool %tmp.1, bool true, bool %tmp.4             ; <bool> [#uses=1]
... which is later simplified by instcombine into an or.
llvm-svn: 21388 
							
						 
						
							2005-04-21 05:31:13 +00:00  
				
					
						
							
							
								 
						
							
								95f16a3ac4 
								
							 
						 
						
							
							
								
								Get rid of this for_each loop  
							
							... 
							
							
							
							llvm-svn: 21253 
							
						 
						
							2005-04-12 18:51:33 +00:00  
				
					
						
							
							
								 
						
							
								0ce80cd542 
								
							 
						 
						
							
							
								
								Fix spelling, patch contributed by Gabor Greif!  
							
							... 
							
							
							
							llvm-svn: 20343 
							
						 
						
							2005-02-27 06:18:25 +00:00  
				
					
						
							
							
								 
						
							
								cc6d75fddf 
								
							 
						 
						
							
							
								
								remove extraneous cast  
							
							... 
							
							
							
							llvm-svn: 20334 
							
						 
						
							2005-02-26 18:33:28 +00:00  
				
					
						
							
							
								 
						
							
								1cca959e5d 
								
							 
						 
						
							
							
								
								Implement Transforms/SimplifyCFG/switch_thread.ll  
							
							... 
							
							
							
							This does a simple form of "jump threading", which eliminates CFG edges that
are provably dead.  This triggers 90 times in the external tests, and
eliminating CFG edges is always always a good thing! :)
llvm-svn: 20300 
							
						 
						
							2005-02-24 06:17:52 +00:00  
				
					
						
							
							
								 
						
							
								a35dfcedd3 
								
							 
						 
						
							
							
								
								switchinst ctor now takes a hint for the number of cases that it will have.  
							
							... 
							
							
							
							llvm-svn: 19898 
							
						 
						
							2005-01-29 00:38:26 +00:00  
				
					
						
							
							
								 
						
							
								3215bb6049 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/DeadSetCC.ll  
							
							... 
							
							
							
							SimplifyCFG is one of those passes that we use for final cleanup: it should
not rely on other passes to clean up its garbage.  This fixes the "why are
trivially dead setcc's in the output of gccas" problem.
llvm-svn: 19212 
							
						 
						
							2005-01-01 16:02:12 +00:00  
				
					
						
							
							
								 
						
							
								4fc998da2e 
								
							 
						 
						
							
							
								
								Fix Regression/Transforms/SimplifyCFG/2004-12-10-SimplifyCFGCrash.ll,  
							
							... 
							
							
							
							and the failure on make_dparser last night.
llvm-svn: 18766 
							
						 
						
							2004-12-10 17:42:31 +00:00  
				
					
						
							
							
								 
						
							
								019445715e 
								
							 
						 
						
							
							
								
								Squelch warning  
							
							... 
							
							
							
							llvm-svn: 18381 
							
						 
						
							2004-11-30 07:47:34 +00:00  
				
					
						
							
							
								 
						
							
								fd8cbc257e 
								
							 
						 
						
							
							
								
								Alkis noticed that this variable is dead.  Thanks!  
							
							... 
							
							
							
							llvm-svn: 18369 
							
						 
						
							2004-11-30 04:01:44 +00:00  
				
					
						
							
							
								 
						
							
								389cfac0d1 
								
							 
						 
						
							
							
								
								If we have something like this:  
							
							... 
							
							
							
							if (x) {
    code
    ...
  } else {
    code
    ...
  }
Turn it into:
  code
  if (x) {
    ...
  } else {
    ...
  }
This reduces code size and in some common cases allows us to completely
eliminate the conditional.  This turns several if/then/else blocks in loops
into straightline code in 179.art, turning the loops into single basic blocks
(good for modsched even!).
Maybe now brg will leave me alone ;-)
llvm-svn: 18366 
							
						 
						
							2004-11-30 00:29:14 +00:00  
				
					
						
							
							
								 
						
							
								93d1e39f3e 
								
							 
						 
						
							
							
								
								Do not compute the predecessor list for a block unless we need it.  
							
							... 
							
							
							
							This speeds up simplifycfg on this program, from 44.87s to 0.29s (with
a profiled build):
 #define CL0(a) case a: goto c;
 #define CL1(a) CL0(a##0) CL0(a##1) CL0(a##2) CL0(a##3) CL0(a##4) CL0(a##5) \
 CL0(a##6) CL0(a##7) CL0(a##8) CL0(a##9)
 #define CL2(a) CL1(a##0) CL1(a##1) CL1(a##2) CL1(a##3) CL1(a##4) CL1(a##5) \
 CL1(a##6) CL1(a##7) CL1(a##8) CL1(a##9)
 #define CL3(a) CL2(a##0) CL2(a##1) CL2(a##2) CL2(a##3) CL2(a##4) CL2(a##5) \
 CL2(a##6) CL2(a##7) CL2(a##8) CL2(a##9)
 #define CL4(a) CL3(a##0) CL3(a##1) CL3(a##2) CL3(a##3) CL3(a##4) CL3(a##5) \
 CL3(a##6) CL3(a##7) CL3(a##8) CL3(a##9)
 void f();
 void a() {
     int b;
  c: switch (b) {
         CL4(1)
     }
 }
This testcase is contrived to expose N^2 behavior, but this patch should speedup
simplifycfg on any programs that use large switch statements.  This testcase
comes from GCC PR17895.
llvm-svn: 17389 
							
						 
						
							2004-11-01 06:53:58 +00:00  
				
					
						
							
							
								 
						
							
								fad217c847 
								
							 
						 
						
							
							
								
								Eliminate compilation warning on uninitialized variable.  
							
							... 
							
							
							
							llvm-svn: 17163 
							
						 
						
							2004-10-22 16:10:39 +00:00  
				
					
						
							
							
								 
						
							
								5edb2f32d0 
								
							 
						 
						
							
							
								
								Simplify code by deleting instructions that preceed unreachable instructions.  
							
							... 
							
							
							
							Simplify code by simplifying terminators that branch to blocks that start
with an unreachable instruction.
llvm-svn: 17116 
							
						 
						
							2004-10-18 04:07:22 +00:00  
				
					
						
							
							
								 
						
							
								45c35b1d1f 
								
							 
						 
						
							
							
								
								When converting phi nodes into select instructions, we shouldn't promote PHI  
							
							... 
							
							
							
							nodes unless we KNOW that we are able to promote all of them.
This fixes: test/Regression/Transforms/SimplifyCFG/PhiNoEliminate.ll
llvm-svn: 16973 
							
						 
						
							2004-10-14 05:13:36 +00:00  
				
					
						
							
							
								 
						
							
								879ce7894c 
								
							 
						 
						
							
							
								
								Do not insert trivially dead select instructions, which allows us to  
							
							... 
							
							
							
							potentially fold more in one pass.
llvm-svn: 16583 
							
						 
						
							2004-09-29 05:43:32 +00:00  
				
					
						
							
							
								 
						
							
								6614946443 
								
							 
						 
						
							
							
								
								Convert code to compile with vc7.1.  
							
							... 
							
							
							
							Patch contributed by Paolo Invernizzi. Thanks Paolo!
llvm-svn: 16368 
							
						 
						
							2004-09-15 17:06:42 +00:00  
				
					
						
							
							
								 
						
							
								a5c04ee50f 
								
							 
						 
						
							
							
								
								Fixes to make LLVM compile with vc7.1.  
							
							... 
							
							
							
							Patch contributed by Paolo Invernizzi!
llvm-svn: 16152 
							
						 
						
							2004-09-03 18:19:51 +00:00  
				
					
						
							
							
								 
						
							
								7c16caa336 
								
							 
						 
						
							
							
								
								Changes For Bug 352  
							
							... 
							
							
							
							Move include/Config and include/Support into include/llvm/Config,
include/llvm/ADT and include/llvm/Support. From here on out, all LLVM
public header files must be under include/llvm/.
llvm-svn: 16137 
							
						 
						
							2004-09-01 22:55:40 +00:00  
				
					
						
							
							
								 
						
							
								902dcf0729 
								
							 
						 
						
							
							
								
								These files don't need to include <iostream> since they include "Support/Debug.h".  
							
							... 
							
							
							
							llvm-svn: 15089 
							
						 
						
							2004-07-21 20:50:33 +00:00  
				
					
						
							
							
								 
						
							
								5823ac1c21 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/BrUnwind.ll  
							
							... 
							
							
							
							llvm-svn: 15022 
							
						 
						
							2004-07-20 01:17:38 +00:00  
				
					
						
							
							
								 
						
							
								ef784f01dd 
								
							 
						 
						
							
							
								
								bug 122:  
							
							... 
							
							
							
							- Minimize redundant isa<GlobalValue> usage
llvm-svn: 14948 
							
						 
						
							2004-07-18 00:32:14 +00:00  
				
					
						
							
							
								 
						
							
								32c518e526 
								
							 
						 
						
							
							
								
								Progress on PR341  
							
							... 
							
							
							
							llvm-svn: 14840 
							
						 
						
							2004-07-15 02:06:12 +00:00  
				
					
						
							
							
								 
						
							
								eb04d9bcb4 
								
							 
						 
						
							
							
								
								Add #include <iostream> since Value.h does not #include it any more.  
							
							... 
							
							
							
							llvm-svn: 14622 
							
						 
						
							2004-07-04 12:19:56 +00:00  
				
					
						
							
							
								 
						
							
								f12c4a3d37 
								
							 
						 
						
							
							
								
								*FINALLY* Fix a really nasty nondeterministic bug that has been haunting us  
							
							... 
							
							
							
							since May 1st.  In this code, the pred iterator was being invalidated sometimes
causing the wrong entries to be added to PHI nodes.
The fix for this is to defererence and safe the *PI value before we hack on
branch instructions, which changes use/def chains, which SOMETIMES invalidates
the iterator.
llvm-svn: 14278 
							
						 
						
							2004-06-21 07:19:01 +00:00  
				
					
						
							
							
								 
						
							
								9734fd0980 
								
							 
						 
						
							
							
								
								Add some DEBUG output to the simplifycfg routines  
							
							... 
							
							
							
							Fix another non-deterministic behavior, this one should actually speed up the
code though as it was doing silly things.
llvm-svn: 14258 
							
						 
						
							2004-06-20 01:13:18 +00:00  
				
					
						
							
							
								 
						
							
								b2b151d297 
								
							 
						 
						
							
							
								
								Do not sort by the address of LLVM ConstantInt* objects.  This produces  
							
							... 
							
							
							
							nondeterministic results that depend on where these objects land in memory.
Instead, sort by the value of the constant, which is stable.
Before this patch, the -simplifycfg pass run from two different compilers
could cause different code to be generated, though it was semantically the
same:
@@ -12258,8 +12258,8 @@
        %s_addr.1 = phi sbyte* [ %s, %entry ], [ %inc.0, %no_exit ]             ; <sbyte*> [#uses=5]
        %tmp.1 = load sbyte* %s_addr.1          ; <sbyte> [#uses=1]
        switch sbyte %tmp.1, label %no_exit [
-                sbyte 0, label %loopexit
                 sbyte 46, label %loopexit
+                sbyte 0, label %loopexit
        ]
We need to stomp all of this stuff out.
llvm-svn: 14243 
							
						 
						
							2004-06-19 07:02:14 +00:00  
				
					
						
							
							
								 
						
							
								be6f06818c 
								
							 
						 
						
							
							
								
								Do not clone arbitrary condition instructions.  
							
							... 
							
							
							
							llvm-svn: 13316 
							
						 
						
							2004-05-02 05:19:36 +00:00  
				
					
						
							
							
								 
						
							
								51a6dbcb65 
								
							 
						 
						
							
							
								
								Do not infinitely "unroll" single BB loops.  
							
							... 
							
							
							
							llvm-svn: 13315 
							
						 
						
							2004-05-02 05:02:03 +00:00  
				
					
						
							
							
								 
						
							
								1e94ed606e 
								
							 
						 
						
							
							
								
								Dont' merge terminators that are needed to select PHI node values.  
							
							... 
							
							
							
							llvm-svn: 13312 
							
						 
						
							2004-05-02 01:00:44 +00:00  
				
					
						
							
							
								 
						
							
								2e93c4275e 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/branch-cond-merge.ll  
							
							... 
							
							
							
							Turning "if (A < B && B < C)" into "if (A < B & B < C)"
llvm-svn: 13311 
							
						 
						
							2004-05-01 23:35:43 +00:00  
				
					
						
							
							
								 
						
							
								4cbd160b45 
								
							 
						 
						
							
							
								
								Fix my missing parens  
							
							... 
							
							
							
							llvm-svn: 13307 
							
						 
						
							2004-05-01 22:41:51 +00:00  
				
					
						
							
							
								 
						
							
								88da6f7b52 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/branch-cond-prop.ll  
							
							... 
							
							
							
							llvm-svn: 13306 
							
						 
						
							2004-05-01 22:36:37 +00:00  
				
					
						
							
							
								 
						
							
								0aa565647c 
								
							 
						 
						
							
							
								
								Fold code like:  
							
							... 
							
							
							
							if (C)
    V1 |= V2;
into:
  Vx = V1 | V2;
  V1 = select C, V1, Vx
when the expression can be evaluated unconditionally and is *cheap* to
execute.  This limited form of if conversion is quite handy in lots of cases.
For example, it turns this testcase into straight-line code:
int in0 ; int in1 ; int in2 ; int in3 ;
int in4 ; int in5 ; int in6 ; int in7 ;
int in8 ; int in9 ; int in10; int in11;
int in12; int in13; int in14; int in15;
long output;
void mux(void) {
  output =
      (in0   ?  0x00000001 : 0) | (in1   ?  0x00000002 : 0) |
      (in2   ?  0x00000004 : 0) | (in3   ?  0x00000008 : 0) |
      (in4   ?  0x00000010 : 0) | (in5   ?  0x00000020 : 0) |
      (in6   ?  0x00000040 : 0) | (in7   ?  0x00000080 : 0) |
      (in8   ?  0x00000100 : 0) | (in9   ?  0x00000200 : 0) |
      (in10  ?  0x00000400 : 0) | (in11  ?  0x00000800 : 0) |
      (in12  ?  0x00001000 : 0) | (in13  ?  0x00002000 : 0) |
      (in14  ?  0x00004000 : 0) | (in15  ?  0x00008000 : 0) ;
}
llvm-svn: 12798 
							
						 
						
							2004-04-09 22:50:22 +00:00  
				
					
						
							
							
								 
						
							
								eed034bcd3 
								
							 
						 
						
							
							
								
								Fix the obvious bug in my previous checkin  
							
							... 
							
							
							
							llvm-svn: 12618 
							
						 
						
							2004-04-02 18:15:10 +00:00  
				
					
						
							
							
								 
						
							
								9f0db32625 
								
							 
						 
						
							
							
								
								Implement Transforms/SimplifyCFG/return-merge.ll  
							
							... 
							
							
							
							This actually causes us to turn code like:
  return C ? A : B;
into a select instruction.
llvm-svn: 12617 
							
						 
						
							2004-04-02 18:13:43 +00:00  
				
					
						
							
							
								 
						
							
								81bdcb90ce 
								
							 
						 
						
							
							
								
								Now that all the code generators support the select instruction, and the instcombine  
							
							... 
							
							
							
							pass can eliminate many nasty cases of them, start generating them in the optimizers
llvm-svn: 12545 
							
						 
						
							2004-03-30 19:44:05 +00:00  
				
					
						
							
							
								 
						
							
								a078f47b39 
								
							 
						 
						
							
							
								
								Fix compilation of mesa, which I broke earlier today  
							
							... 
							
							
							
							llvm-svn: 12465 
							
						 
						
							2004-03-17 02:02:47 +00:00  
				
					
						
							
							
								 
						
							
								a64923ad26 
								
							 
						 
						
							
							
								
								Do not copy gigantic switch instructions  
							
							... 
							
							
							
							llvm-svn: 12441 
							
						 
						
							2004-03-16 19:45:22 +00:00  
				
					
						
							
							
								 
						
							
								d3e6ae263c 
								
							 
						 
						
							
							
								
								Implement switch->br and br->switch folding by ripping out the switch->switch  
							
							... 
							
							
							
							and br->br code and generalizing it.  This allows us to compile code like this:
int test(Instruction *I) {
  if (isa<CastInst>(I))
    return foo(7);
  else if (isa<BranchInst>(I))
    return foo(123);
  else if (isa<UnwindInst>(I))
    return foo(1241);
  else if (isa<SetCondInst>(I))
    return foo(1);
  else if (isa<VAArgInst>(I))
    return foo(42);
  return foo(-1);
}
into:
int %_Z4testPN4llvm11InstructionE("struct.llvm::Instruction"* %I) {
entry:
        %tmp.1.i.i.i.i.i.i.i = getelementptr "struct.llvm::Instruction"* %I, long 0, ubyte 4            ; <uint*> [#uses=1]
        %tmp.2.i.i.i.i.i.i.i = load uint* %tmp.1.i.i.i.i.i.i.i          ; <uint> [#uses=2]
        %tmp.2.i.i.i.i.i.i = seteq uint %tmp.2.i.i.i.i.i.i.i, 27                ; <bool> [#uses=0]
        switch uint %tmp.2.i.i.i.i.i.i.i, label %endif.0 [
                 uint 27, label %then.0
                 uint 2, label %then.1
                 uint 5, label %then.2
                 uint 14, label %then.3
                 uint 15, label %then.3
                 uint 16, label %then.3
                 uint 17, label %then.3
                 uint 18, label %then.3
                 uint 19, label %then.3
                 uint 32, label %then.4
        ]
...
As well as handling the cases in 176.gcc and many other programs more effectively.
llvm-svn: 11964 
							
						 
						
							2004-02-28 21:28:10 +00:00  
				
					
						
							
							
								 
						
							
								21e941fbfd 
								
							 
						 
						
							
							
								
								turn things like:  
							
							... 
							
							
							
							if (X == 0 || X == 2)
...where the comparisons and branches are in different blocks... into a switch
instruction.  This comes up a lot in various programs, and works well with
the switch/switch merging code I checked earlier.  For example, this testcase:
int switchtest(int C) {
  return C == 0 ? f(123) :
         C == 1 ? f(3123) :
         C == 4 ? f(312) :
         C == 5 ? f(1234): f(444);
}
is converted into this:
        switch int %C, label %cond_false.3 [
                 int 0, label %cond_true.0
                 int 1, label %cond_true.1
                 int 4, label %cond_true.2
                 int 5, label %cond_true.3
        ]
instead of a whole bunch of conditional branches.
Admittedly the code is ugly, and incomplete.  To be complete, we need to add
br -> switch merging and switch -> br merging.  For example, this testcase:
struct foo { int Q, R, Z; };
#define A (X->Q+X->R * 123)
int test(struct foo *X) {
  return A  == 123 ? X1() :
        A == 12321 ? X2():
        (A == 111 || A == 222) ? X3() :
        A == 875 ? X4() : X5();
}
Gets compiled to this:
        switch int %tmp.7, label %cond_false.2 [
                 int 123, label %cond_true.0
                 int 12321, label %cond_true.1
                 int 111, label %cond_true.2
                 int 222, label %cond_true.2
        ]
...
cond_false.2:           ; preds = %entry
        %tmp.52 = seteq int %tmp.7, 875         ; <bool> [#uses=1]
        br bool %tmp.52, label %cond_true.3, label %cond_false.3
where the branch could be folded into the switch.
This kind of thing occurs *ALL OF THE TIME*, especially in programs like
176.gcc, which is a horrible mess of code.  It contains stuff like *shudder*:
#define SWITCH_TAKES_ARG(CHAR) \
  (   (CHAR) == 'D' \
   || (CHAR) == 'U' \
   || (CHAR) == 'o' \
   || (CHAR) == 'e' \
   || (CHAR) == 'u' \
   || (CHAR) == 'I' \
   || (CHAR) == 'm' \
   || (CHAR) == 'L' \
   || (CHAR) == 'A' \
   || (CHAR) == 'h' \
   || (CHAR) == 'z')
and
#define CONST_OK_FOR_LETTER_P(VALUE, C)                 \
  ((C) == 'I' ? SMALL_INTVAL (VALUE)                    \
   : (C) == 'J' ? SMALL_INTVAL (-(VALUE))               \
   : (C) == 'K' ? (unsigned)(VALUE) < 32                \
   : (C) == 'L' ? ((VALUE) & 0xffff) == 0               \
   : (C) == 'M' ? integer_ok_for_set (VALUE)            \
   : (C) == 'N' ? (VALUE) < 0                           \
   : (C) == 'O' ? (VALUE) == 0                          \
   : (C) == 'P' ? (VALUE) >= 0                          \
   : 0)
and
#define LEGITIMIZE_ADDRESS(X,OLDX,MODE,WIN)                     \
{                                                               \
  if (GET_CODE (X) == PLUS && CONSTANT_ADDRESS_P (XEXP (X, 1))) \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 0),                   \
                   copy_to_mode_reg (SImode, XEXP (X, 1)));     \
  if (GET_CODE (X) == PLUS && CONSTANT_ADDRESS_P (XEXP (X, 0))) \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 1),                   \
                   copy_to_mode_reg (SImode, XEXP (X, 0)));     \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 0)) == MULT)   \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 1),                   \
                   force_operand (XEXP (X, 0), 0));             \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == MULT)   \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 0),                   \
                   force_operand (XEXP (X, 1), 0));             \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 0)) == PLUS)   \
    (X) = gen_rtx (PLUS, Pmode, force_operand (XEXP (X, 0), NULL_RTX),\
                   XEXP (X, 1));                                \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == PLUS)   \
    (X) = gen_rtx (PLUS, Pmode, XEXP (X, 0),                    \
                   force_operand (XEXP (X, 1), NULL_RTX));      \
  if (GET_CODE (X) == SYMBOL_REF || GET_CODE (X) == CONST       \
           || GET_CODE (X) == LABEL_REF)                        \
    (X) = legitimize_address (flag_pic, X, 0, 0);               \
  if (memory_address_p (MODE, X))                               \
    goto WIN; }
and others.  These macros get used multiple times of course.  These are such
lovely candidates for macros, aren't they?  :)
This code also nicely handles LLVM constructs that look like this:
  if (isa<CastInst>(I))
   ...
  else if (isa<BranchInst>(I))
   ...
  else if (isa<SetCondInst>(I))
   ...
  else if (isa<UnwindInst>(I))
   ...
  else if (isa<VAArgInst>(I))
   ...
where the isa can obviously be a dyn_cast as well.  Switch instructions are a
good thing.
llvm-svn: 11870 
							
						 
						
							2004-02-26 07:13:46 +00:00  
				
					
						
							
							
								 
						
							
								90ea78edba 
								
							 
						 
						
							
							
								
								If a block is made dead, make sure to promptly remove it.  
							
							... 
							
							
							
							llvm-svn: 11799 
							
						 
						
							2004-02-24 16:09:21 +00:00  
				
					
						
							
							
								 
						
							
								a2ab489135 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/switch_switch_fold.ll  
							
							... 
							
							
							
							This case occurs many times in various benchmarks, especially when combined
with the previous patch.  This allows it to get stuff like:
  if (X == 4 || X == 3)
    if (X == 5 || X == 8)
and
switch (X) {
case 4: case 5: case 6:
  if (X == 4 || X == 5)
llvm-svn: 11797 
							
						 
						
							2004-02-24 07:23:58 +00:00  
				
					
						
							
							
								 
						
							
								3cd98f054a 
								
							 
						 
						
							
							
								
								Rearrange code a bit  
							
							... 
							
							
							
							llvm-svn: 11793 
							
						 
						
							2004-02-24 05:54:22 +00:00  
				
					
						
							
							
								 
						
							
								6f4b45acf5 
								
							 
						 
						
							
							
								
								Implement: test/Regression/Transforms/SimplifyCFG/switch_create.ll  
							
							... 
							
							
							
							This turns code like this:
  if (X == 4 | X == 7)
and
  if (X != 4 & X != 7)
into switch instructions.
llvm-svn: 11792 
							
						 
						
							2004-02-24 05:38:11 +00:00  
				
					
						
							
							
								 
						
							
								e42732e75f 
								
							 
						 
						
							
							
								
								Implement test/Regression/Transforms/SimplifyCFG/UncondBranchToReturn.ll,  
							
							... 
							
							
							
							see the testcase for the reasoning.
llvm-svn: 11496 
							
						 
						
							2004-02-16 06:35:48 +00:00  
				
					
						
							
							
								 
						
							
								18d1f19fba 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/PhiEliminate.ll  
							
							... 
							
							
							
							Having a proper 'select' instruction would allow the elimination of a lot
of the special case cruft in this patch, but we don't have one yet.
llvm-svn: 11307 
							
						 
						
							2004-02-11 03:36:04 +00:00  
				
					
						
							
							
								 
						
							
								838b845781 
								
							 
						 
						
							
							
								
								The hasConstantReferences predicate always returns false.  
							
							... 
							
							
							
							llvm-svn: 11301 
							
						 
						
							2004-02-11 01:17:07 +00:00  
				
					
						
							
							
								 
						
							
								fae8ab3088 
								
							 
						 
						
							
							
								
								rename the "exceptional" destination of an invoke instruction to the 'unwind' dest  
							
							... 
							
							
							
							llvm-svn: 11202 
							
						 
						
							2004-02-08 21:44:31 +00:00  
				
					
						
							
							
								 
						
							
								df3c342a4c 
								
							 
						 
						
							
							
								
								Finegrainify namespacification  
							
							... 
							
							
							
							llvm-svn: 10727 
							
						 
						
							2004-01-09 06:12:26 +00:00  
				
					
						
							
							
								 
						
							
								960707c335 
								
							 
						 
						
							
							
								
								Put all LLVM code into the llvm namespace, as per bug 109.  
							
							... 
							
							
							
							llvm-svn: 9903 
							
						 
						
							2003-11-11 22:41:34 +00:00  
				
					
						
							
							
								 
						
							
								482202a601 
								
							 
						 
						
							
							
								
								Added LLVM project notice to the top of every C++ source file.  
							
							... 
							
							
							
							Header files will be on the way.
llvm-svn: 9298 
							
						 
						
							2003-10-20 19:43:21 +00:00  
				
					
						
							
							
								 
						
							
								8b2bd4ed47 
								
							 
						 
						
							
							
								
								Fix spelling.  
							
							... 
							
							
							
							llvm-svn: 9027 
							
						 
						
							2003-10-10 17:57:28 +00:00  
				
					
						
							
							
								 
						
							
								04ecefe232 
								
							 
						 
						
							
							
								
								Eliminate support for the llvm.unwind intrinisic, using the Unwind instruction instead  
							
							... 
							
							
							
							llvm-svn: 8411 
							
						 
						
							2003-09-08 19:44:26 +00:00  
				
					
						
							
							
								 
						
							
								3f5823f131 
								
							 
						 
						
							
							
								
								Implement SimplifyCFG/InvokeEliminate.ll  
							
							... 
							
							
							
							llvm-svn: 8126 
							
						 
						
							2003-08-24 18:36:16 +00:00  
				
					
						
							
							
								 
						
							
								031340a551 
								
							 
						 
						
							
							
								
								Fix bug: SimplifyCFG/2003-08-17-BranchFoldOrdering.ll  
							
							... 
							
							
							
							llvm-svn: 7921 
							
						 
						
							2003-08-17 19:41:53 +00:00  
				
					
						
							
							
								 
						
							
								edc8c54e16 
								
							 
						 
						
							
							
								
								Fix bug: SimplifyCFG/2003-08-05-InvokeCrash.ll  
							
							... 
							
							
							
							Fix bug: SimplifyCFG/2003-08-05-MishandleInvoke.ll
llvm-svn: 7599 
							
						 
						
							2003-08-05 16:27:44 +00:00  
				
					
						
							
							
								 
						
							
								889f620841 
								
							 
						 
						
							
							
								
								Remove unnecesary &*'s  
							
							... 
							
							
							
							llvm-svn: 5872 
							
						 
						
							2003-04-23 16:37:45 +00:00  
				
					
						
							
							
								 
						
							
								569a57f9ff 
								
							 
						 
						
							
							
								
								Fix bug: SimplifyCFG/2003-03-07-DominateProblem.ll  
							
							... 
							
							
							
							llvm-svn: 5722 
							
						 
						
							2003-03-07 18:13:41 +00:00  
				
					
						
							
							
								 
						
							
								e54d214fcb 
								
							 
						 
						
							
							
								
								Implement CFGSimplify/PhiBlockMerge*.ll  
							
							... 
							
							
							
							llvm-svn: 5702 
							
						 
						
							2003-03-05 21:36:33 +00:00  
				
					
						
							
							
								 
						
							
								31116bafed 
								
							 
						 
						
							
							
								
								Implement testcase CFGSimplify/EqualPHIEdgeBlockMerge.ll  
							
							... 
							
							
							
							llvm-svn: 5699 
							
						 
						
							2003-03-05 21:01:52 +00:00  
				
					
						
							
							
								 
						
							
								632df28deb 
								
							 
						 
						
							
							
								
								Fix spelling of `propagate'.  
							
							... 
							
							
							
							llvm-svn: 4423 
							
						 
						
							2002-10-29 23:06:16 +00:00  
				
					
						
							
							
								 
						
							
								a704ac8a66 
								
							 
						 
						
							
							
								
								Changes to support PHINode::removeIncoming changes  
							
							... 
							
							
							
							llvm-svn: 4079 
							
						 
						
							2002-10-08 21:36:33 +00:00  
				
					
						
							
							
								 
						
							
								d6dcd8ec32 
								
							 
						 
						
							
							
								
								Fix bug: SimplifyCFG/2002-09-24-PHIAssertion.ll  
							
							... 
							
							
							
							llvm-svn: 3913 
							
						 
						
							2002-09-24 16:09:17 +00:00  
				
					
						
							
							
								 
						
							
								5325c5f340 
								
							 
						 
						
							
							
								
								Minor cleanups  
							
							... 
							
							
							
							llvm-svn: 3904 
							
						 
						
							2002-09-24 00:09:26 +00:00  
				
					
						
							
							
								 
						
							
								1cec4d90cd 
								
							 
						 
						
							
							
								
								Allow folding of basic blocks that have PHI nodes in them, fixing "bug":  
							
							... 
							
							
							
							test/Regression/Transforms/SimplifyCFG/2002-06-24-PHINode.ll
llvm-svn: 3128 
							
						 
						
							2002-07-29 21:26:30 +00:00  
				
					
						
							
							
								 
						
							
								fda72b1aad 
								
							 
						 
						
							
							
								
								*** empty log message ***  
							
							... 
							
							
							
							llvm-svn: 2777 
							
						 
						
							2002-06-25 16:12:52 +00:00  
				
					
						
							
							
								 
						
							
								466a049b67 
								
							 
						 
						
							
							
								
								Add implementation of SimplifyCFG  
							
							... 
							
							
							
							llvm-svn: 2701 
							
						 
						
							2002-05-21 20:50:24 +00:00