Commit Graph

2481 Commits

Author SHA1 Message Date
Owen Anderson 505adff3f0 Make Loop able to verify that it is in LCSSA-form, and have the LCSSA pass assert
on this.

llvm-svn: 28738
2006-06-09 18:33:30 +00:00
Evan Cheng 398f70292c RewriteExpr, either the new PHI node of induction variable or the
post-increment value, should be first cast to the appropriated type (to the
type of the common expr). Otherwise, the rewrite of a use based on (common +
iv) may end up with an incorrect type.

llvm-svn: 28735
2006-06-09 00:12:42 +00:00
Owen Anderson 5d029264ec Update some comments, and expose LCSSAID in preparation for having other passes
require LCSSA.

llvm-svn: 28734
2006-06-08 20:02:53 +00:00
Reid Spencer d4b795902c Fix a spello in a comment.
llvm-svn: 28714
2006-06-07 21:24:10 +00:00
Chris Lattner 95cebb082f Fix a bug in a recent patch. This fixes UnitTests/Vector/Altivec/casts.c on
PPC/altivec

llvm-svn: 28698
2006-06-06 22:26:02 +00:00
Owen Anderson ac601b4c4b Fix some formatting, and use inLoop() when appropriate.
llvm-svn: 28694
2006-06-06 04:36:36 +00:00
Owen Anderson 9e81c1bb03 Stop a memory leak, and update some comments.
llvm-svn: 28693
2006-06-06 04:28:30 +00:00
Owen Anderson 766f90b08e Some more clean-up, and squash an IDF-Phi related bug.
llvm-svn: 28680
2006-06-04 00:55:19 +00:00
Owen Anderson eb33815f1b Various clean-ups suggested by Chris.
llvm-svn: 28678
2006-06-04 00:02:23 +00:00
Owen Anderson d00eacc4f9 Fix a bug in Phi-noded insertion. Also, update some comments to reflect what's
actually going on.

llvm-svn: 28677
2006-06-03 23:22:50 +00:00
Chris Lattner 540886f0ae Remove unneeded hook. Patch by Anton K. Thanks!
llvm-svn: 28664
2006-06-02 19:11:46 +00:00
Chris Lattner 02e0b4ddb7 Force anything that #includes llvm/Transforms/Utils/UnifyFunctionExitNodes.h
to link in the implementation.  Thanks to Anton Korobeynikov for figuring out
what was going on here.

llvm-svn: 28660
2006-06-02 18:40:06 +00:00
Chris Lattner cdf2b1fc30 Remove dead #include
llvm-svn: 28642
2006-06-01 20:02:28 +00:00
Chris Lattner cc340c02a4 Make the "pruning cloner" smarter. As it propagates constants through the
code (while cloning) it often gets the branch/switch instructions.  Since it
knows that edges of the CFG are dead, it need not clone (or even look) at
the obviously dead blocks.  This should speed up the inliner substantially on
code where there are lots of inlinable calls to functions with constant
arguments.  On C++ code in particular, this kicks in.

llvm-svn: 28641
2006-06-01 19:19:23 +00:00
Chris Lattner f905a7b994 Silence a -pedantic warning.
llvm-svn: 28632
2006-06-01 17:16:21 +00:00
Owen Anderson 619e4ba57f Remove a FIXME that was fixed with my last patch.
llvm-svn: 28619
2006-06-01 06:07:40 +00:00
Owen Anderson cd76fa04a1 More cleanups. Also, add a special case for updating PHI nodes, and
reimplement getValueDominatingFunction to walk the DominanceTree rather than
just searching blindly.

llvm-svn: 28618
2006-06-01 06:05:47 +00:00
Chris Lattner 1df0e98ac2 Swap the order of operands created here. For +&|^, the order doesn't matter,
but for sub, it really does!  Fix fixes a miscompilation of fibheap_cut in
llvmgcc4.

llvm-svn: 28600
2006-05-31 21:14:00 +00:00
Owen Anderson dad8c57340 Extract a huge loop into a helper method. Fix a few iterator-invalidation bugs.
llvm-svn: 28599
2006-05-31 20:55:06 +00:00
Owen Anderson 8a8f278f15 Add Use replacement. Assuming there is nothing horribly wrong with this, LCSSA
is now theoretically feature-complete.  It has not, however, been thoroughly
test, and is still considered experimental.

llvm-svn: 28529
2006-05-29 01:00:00 +00:00
Owen Anderson 152d063ccb Major think-o. Iterate over all live out-of-loop values, and perform the
other calculations on each individually, rather than trying to delay it and do
them all at the end.

llvm-svn: 28527
2006-05-28 19:33:28 +00:00
Owen Anderson 1310e42803 Make LCSSA insert proper Phi nodes throughout the rest of the CFG by computing
the iterated Dominance Frontier of the loop-closure Phi's.  This is the
second phase of the LCSSA pass.  The third phase (coming soon) will be to
update all uses of loop variables to use the loop-closure Phi's instead.

llvm-svn: 28524
2006-05-27 18:47:11 +00:00
Chris Lattner 67c424e010 Fix some regression from the inliner patch I committed last night. This fixes
ldecod, lencod, and SPASS.

llvm-svn: 28523
2006-05-27 17:28:13 +00:00
Chris Lattner be853d77e9 Switch the inliner over to using CloneAndPruneFunctionInto. This effectively
makes it so that it constant folds instructions on the fly.  This is good
for several reasons:

0. Many instructions are constant foldable after inlining, particularly if
   inlining a call with constant arguments.
1. Without this, the inliner has to allocate memory for all of the instructions
   that can be constant folded, then a subsequent pass has to delete them.  This
   gets the job done without this extra work.
2. This makes the inliner *pass* a bit more aggressive: in particular, it
   partially solves a phase order issue where the inliner would inline lots
   of code that folds away to nothing, but think that the resultant function
   is big because of this code that will be gone.  Now the code never exists.

This is the first part of a 2-step process.  The second part will be smart
enough to see when this implicit constant folding propagates a constant into
a branch or switch instruction, making CFG edges dead.

This implements Transforms/Inline/inline_constprop.ll

llvm-svn: 28521
2006-05-27 01:28:04 +00:00
Chris Lattner 3df13f4f22 Implement a new method, CloneAndPruneFunctionInto, as documented.
llvm-svn: 28519
2006-05-27 01:22:24 +00:00
Chris Lattner bc3c879fcf Refactor some code to expose an interface to constant fold and instruction given it's opcode, typeand operands.
llvm-svn: 28517
2006-05-27 01:18:04 +00:00
Owen Anderson b4e16996f1 A few small clean-ups, and the addition of an LCSSA statistic.
llvm-svn: 28512
2006-05-27 00:31:37 +00:00
Owen Anderson 6e047ab8fc Fix a copy-and-paste-o that would break some compilers.
llvm-svn: 28507
2006-05-26 21:19:17 +00:00
Owen Anderson f3dd3e2bfd Clean up and refactor LCSSA a bunch. It should also run faster now, though
there's still a lot of work to be done on it.

llvm-svn: 28506
2006-05-26 21:11:53 +00:00
Chris Lattner dab43b2b0e Implement Transforms/InstCombine/store.ll:test2.
llvm-svn: 28503
2006-05-26 19:19:20 +00:00
Owen Anderson 8eca8910b6 Skeletal LCSSA pass. This is currently non-functional. Expect functionality
and documentation updates soo.

llvm-svn: 28495
2006-05-26 13:58:26 +00:00
Chris Lattner 0e47716e69 Transform things like (splat(splat)) -> splat
llvm-svn: 28490
2006-05-26 00:29:06 +00:00
Chris Lattner 12249be286 Introduce a helper function that simplifies interpretation of shuffle masks.
No functionality change.

llvm-svn: 28489
2006-05-25 23:48:38 +00:00
Chris Lattner 99155be33f Turn (cast (shuffle (cast)) -> shuffle (cast) if it reduces the # casts in
the program.  This exposes more opportunities for the instcombiner, and implements
vec_shuffle.ll:test6

llvm-svn: 28487
2006-05-25 23:24:33 +00:00
Chris Lattner 83f6578b0c extract element from a shuffle vector can be trivially turned into an
extractelement from the SV's source.  This implement vec_shuffle.ll:test[45]

llvm-svn: 28485
2006-05-25 22:53:38 +00:00
Chris Lattner 0853700582 Revert a patch that is unsafe, due to out of range array accesses in inner
array scopes possibly accessing valid memory in outer subscripts.

llvm-svn: 28478
2006-05-25 21:25:12 +00:00
Chris Lattner a643d528bd Patch for a new instcombine xform, patch contributed by Nick Lewycky!
This implements Transforms/InstCombine/2006-05-10-InvalidIndexUndef.ll

llvm-svn: 28450
2006-05-24 17:34:30 +00:00
Chris Lattner aa2372562e Patches to make the LLVM sources more -pedantic clean. Patch provided
by Anton Korobeynikov!  This is a step towards closing PR786.

llvm-svn: 28447
2006-05-24 17:04:05 +00:00
Chris Lattner d0622b6894 Silence a bogus gcc warning
llvm-svn: 28422
2006-05-20 23:14:03 +00:00
Reid Spencer 2452c94df4 Fix a doxygen problem and break lines at 80 columns
llvm-svn: 28395
2006-05-19 19:09:46 +00:00
Chris Lattner e4cb4768fa Declare that lowerinvoke doesn't interact with other lowering passes.
Patch written by Domagoj Babic!

llvm-svn: 28367
2006-05-17 21:05:27 +00:00
Chris Lattner 2e266807c3 Add a CloneModule call that exposes the mapping of values from the old module
to the new module.  Patch provided by Nick Lewycky!

llvm-svn: 28349
2006-05-17 18:05:35 +00:00
Chris Lattner 35515557c7 remove some dead code identified by coverity
llvm-svn: 28289
2006-05-14 18:45:44 +00:00
Chris Lattner 3237da073e remove dead variables
llvm-svn: 28286
2006-05-14 18:33:57 +00:00
Evan Cheng 18d0438148 Backing out last check-in for now. It's causing an infinite loop gccas lencode.
llvm-svn: 28284
2006-05-14 06:46:03 +00:00
Chris Lattner 3987a8532d Add/Sub/Mul are safe to promote here as well. Incrementing a single-bit
bitfield now gives this code:

_plus:
        lwz r2, 0(r3)
        rlwimi r2, r2, 0, 1, 31
        xoris r2, r2, 32768
        stw r2, 0(r3)
        blr

instead of this:

_plus:
        lwz r2, 0(r3)
        srwi r4, r2, 31
        slwi r4, r4, 31
        addis r4, r4, -32768
        rlwimi r2, r4, 0, 0, 0
        stw r2, 0(r3)
        blr

this can obviously still be improved.

llvm-svn: 28275
2006-05-13 02:16:08 +00:00
Chris Lattner 1ebbe6a22e Implement simple promotion for cast elimination in instcombine. This is
currently very limited, but can be extended in the future.  For example,
we now compile:

uint %test30(uint %c1) {
        %c2 = cast uint %c1 to ubyte
        %c3 = xor ubyte %c2, 1
        %c4 = cast ubyte %c3 to uint
        ret uint %c4
}

to:

_xor:
        movzbl 4(%esp), %eax
        xorl $1, %eax
        ret

instead of:

_xor:
        movb $1, %al
        xorb 4(%esp), %al
        movzbl %al, %eax
        ret

More impressively, we now compile:

struct B { unsigned bit : 1; };
void xor(struct B *b) { b->bit = b->bit ^ 1; }

To (X86/PPC):

_xor:
        movl 4(%esp), %eax
        xorl $-2147483648, (%eax)
        ret
_xor:
        lwz r2, 0(r3)
        xoris r2, r2, 32768
        stw r2, 0(r3)
        blr

instead of (X86/PPC):

_xor:
        movl 4(%esp), %eax
        movl (%eax), %ecx
        movl %ecx, %edx
        shrl $31, %edx
        # TRUNCATE movb %dl, %dl
        xorb $1, %dl
        movzbl %dl, %edx
        andl $2147483647, %ecx
        shll $31, %edx
        orl %ecx, %edx
        movl %edx, (%eax)
        ret

_xor:
        lwz r2, 0(r3)
        srwi r4, r2, 31
        xori r4, r4, 1
        rlwimi r2, r4, 31, 0, 0
        stw r2, 0(r3)
        blr

This implements InstCombine/cast.ll:test30.

llvm-svn: 28273
2006-05-13 02:06:03 +00:00
Chris Lattner cd60d38b30 Remove some dead variables.
Fix a nasty bug in the memcmp optimizer where we used the wrong variable!

llvm-svn: 28269
2006-05-12 23:35:26 +00:00
Chris Lattner 94acc47654 Remove dead stuff
llvm-svn: 28268
2006-05-12 23:32:01 +00:00
Chris Lattner 1443bc52be Refactor some code, making it simpler.
When doing the initial pass of constant folding, if we get a constantexpr,
simplify the constant expr like we would do if the constant is folded in the
normal loop.

This fixes the missed-optimization regression in
Transforms/InstCombine/getelementptr.ll last night.

llvm-svn: 28224
2006-05-11 17:11:52 +00:00
Chris Lattner a36ee4ea34 Two changes:
1. Implement InstCombine/deadcode.ll by not adding instructions in unreachable
   blocks (due to constants in conditional branches/switches) to the worklist.
   This causes them to be deleted before instcombine starts up, leading to
   better optimization.

2. In the prepass over instructions, do trivial constprop/dce as we go.  This
   has the effect of improving the effectiveness of #1.  In addition, it
   *significantly* speeds up instcombine on test cases with large amounts of
   constant folding code (for example, that produced by code specialization
   or partial evaluation).  In one example, it speeds up instcombine from
   0.0589s to 0.0224s with a release build (a 2.6x speedup).

llvm-svn: 28215
2006-05-10 19:00:36 +00:00
Chris Lattner 4fe87d67c4 Patch to make some xforms preserve each other. Patch contributed by
Domagoj Babic!

llvm-svn: 28181
2006-05-09 04:13:41 +00:00
Chris Lattner 1d441adfbf Move some code around.
Make the "fold (and (cast A), (cast B)) -> (cast (and A, B))" transformation
only apply when both casts really will cause code to be generated.  If one or
both doesn't, then this xform doesn't remove a cast.

This fixes Transforms/InstCombine/2006-05-06-Infloop.ll

llvm-svn: 28141
2006-05-06 09:00:16 +00:00
Chris Lattner e745c7de0e Fix an infinite loop compiling oggenc last night.
llvm-svn: 28128
2006-05-05 20:51:30 +00:00
Chris Lattner 3af1053488 Implement InstCombine/cast.ll:test29
llvm-svn: 28126
2006-05-05 06:39:07 +00:00
Chris Lattner fb29692055 Fix Transforms/InstCombine/2006-05-04-DemandedBitCrash.ll
llvm-svn: 28101
2006-05-04 17:33:35 +00:00
Chris Lattner 2d3a02725d Add pass ID's for various passes, so they can be AddRequiredID. Patch by
Domagoj Babic!

llvm-svn: 28048
2006-05-02 04:24:36 +00:00
Chris Lattner 655d08fda8 Fix InstCombine/2006-04-28-ShiftShiftLongLong.ll
llvm-svn: 28019
2006-04-28 22:21:41 +00:00
Chris Lattner e63d808b6e Fix Transforms/Reassociate/2006-04-27-ReassociateVector.ll
llvm-svn: 28007
2006-04-28 04:14:49 +00:00
Chris Lattner b6cb64b7e6 Add support for inserting undef into a vector. This implements
Transforms/InstCombine/vec_insert_to_shuffle.ll

llvm-svn: 27997
2006-04-27 21:14:21 +00:00
Chris Lattner f98b4aa2e7 Fix some nondeterminstic behavior in the mem2reg pass that (in addition to
nondeterminism being bad) could cause some trivial missed optimizations (dead
phi nodes being left around for later passes to clean up).

With this, llvm-gcc4 now bootstraps and correctly compares.  I don't know
why I never tried to do it before... :)

llvm-svn: 27984
2006-04-27 01:14:43 +00:00
Chris Lattner dae49df407 Fix Transforms/ScalarRepl/2006-04-20-PromoteCrash.ll
llvm-svn: 27912
2006-04-20 20:48:50 +00:00
Andrew Lenharth f89e630b2f Make code match cvs commit message :)
llvm-svn: 27881
2006-04-20 15:41:37 +00:00
Andrew Lenharth 61eae29ad6 If we can convert the return pointer type into an integer that IntPtrType
can be converted to losslessly, we can continue the conversion to a direct call.

llvm-svn: 27880
2006-04-20 14:56:47 +00:00
Chris Lattner 36dd7c98d1 Turn x86 unaligned load/store intrinsics into aligned load/store instructions
if the pointer is known aligned.

llvm-svn: 27781
2006-04-17 22:26:56 +00:00
Chris Lattner 9095186deb Fix a bug in the 'shuffle(undef,x,mask) -> shuffle(x, undef,mask')' xform
Make the insert/extract elt -> shuffle code more aggressive.

This fixes CodeGen/PowerPC/vec_shuffle.ll

llvm-svn: 27728
2006-04-16 00:51:47 +00:00
Chris Lattner 34cebe785d Canonicalize shuffle(undef,x,mask) -> shuffle(x, undef,mask').
llvm-svn: 27727
2006-04-16 00:03:56 +00:00
Chris Lattner 39fac448d6 significant cleanups to code that uses insert/extractelt heavily. This builds
maximal shuffles out of them where possible.

llvm-svn: 27717
2006-04-15 01:39:45 +00:00
Chris Lattner 3323ce165d Teach scalarrepl to promote unions of vectors and floats, producing
insert/extractelement operations.  This implements
Transforms/ScalarRepl/vector_promote.ll

llvm-svn: 27710
2006-04-14 21:42:41 +00:00
Andrew Lenharth 92cf71f6d7 linear -> constant time
llvm-svn: 27652
2006-04-13 13:43:31 +00:00
Reid Spencer 13a1a7a4a6 Get rid of a signed/unsigned compare warning.
llvm-svn: 27625
2006-04-12 19:28:15 +00:00
Chris Lattner b19a5c661b Turn casts into getelementptr's when possible. This enables SROA to be more
aggressive in some cases where LLVMGCC 4 is inserting casts for no reason.

This implements InstCombine/cast.ll:test27/28.

llvm-svn: 27620
2006-04-12 18:09:35 +00:00
Chris Lattner 2d37f920ad Implement vec_shuffle.ll:test3
llvm-svn: 27573
2006-04-10 23:06:36 +00:00
Chris Lattner fbb77a408b Implement InstCombine/vec_shuffle.ll:test[12]
llvm-svn: 27571
2006-04-10 22:45:52 +00:00
Andrew Lenharth a9cdcca3c3 Add a simple pass to make sure that all (non-library) calls to malloc and free
are visible to analysis as intrinsics.  That is, make sure someone doesn't pass
free around by address in some struct (as happens in say 176.gcc).

This doesn't get rid of any indirect calls, just ensure calls to free and malloc
are always direct.

llvm-svn: 27560
2006-04-10 19:26:09 +00:00
Chris Lattner 17bd60588c Add supprot for shufflevector
llvm-svn: 27513
2006-04-08 01:19:12 +00:00
Chris Lattner 8ec0205de4 Fix inlining of insert/extract element constantexprs
llvm-svn: 27478
2006-04-07 04:41:03 +00:00
Chris Lattner e79d249c29 Lower vperm(x,y, mask) -> shuffle(x,y,mask) if mask is constant. This allows
us to compile oh-so-realistic stuff like this:

 vec_vperm(A, B, (vector unsigned char){14});

to:
        vspltb v0, v0, 14

instead of:

        vspltisb v0, 14
        vperm v0, v2, v1, v0

llvm-svn: 27452
2006-04-06 19:19:17 +00:00
Chris Lattner caba72b6ff vector casts of casts are eliminable. Transform this:
%tmp = cast <4 x uint> %tmp to <4 x int>                ; <<4 x int>> [#uses=1]
        %tmp = cast <4 x int> %tmp to <4 x float>               ; <<4 x float>> [#uses=1]

into:

        %tmp = cast <4 x uint> %tmp to <4 x float>              ; <<4 x float>> [#uses=1]

llvm-svn: 27355
2006-04-02 05:43:13 +00:00
Chris Lattner ebca476b27 Allow transforming this:
%tmp = cast <4 x uint>* %testData to <4 x int>*         ; <<4 x int>*> [#uses=1]
        %tmp = load <4 x int>* %tmp             ; <<4 x int>> [#uses=1]

to this:

        %tmp = load <4 x uint>* %testData               ; <<4 x uint>> [#uses=1]
        %tmp = cast <4 x uint> %tmp to <4 x int>                ; <<4 x int>> [#uses=1]

llvm-svn: 27353
2006-04-02 05:37:12 +00:00
Chris Lattner f42d0aeda1 Turn altivec lvx/stvx intrinsics into loads and stores. This allows the
elimination of one load from this:

int AreSecondAndThirdElementsBothNegative( vector float *in ) {
#define QNaN 0x7FC00000
const vector unsigned int testData = (vector unsigned int)( QNaN, 0, 0, QNaN );
vector float test = vec_ld( 0, (float*) &testData );
return ! vec_any_ge( test, *in );
}

Now generating:

_AreSecondAndThirdElementsBothNegative:
        mfspr r2, 256
        oris r4, r2, 49152
        mtspr 256, r4
        li r4, lo16(LCPI1_0)
        lis r5, ha16(LCPI1_0)
        addi r6, r1, -16
        lvx v0, r5, r4
        stvx v0, 0, r6
        lvx v1, 0, r3
        vcmpgefp. v0, v0, v1
        mfcr r3, 2
        rlwinm r3, r3, 27, 31, 31
        xori r3, r3, 1
        cntlzw r3, r3
        srwi r3, r3, 5
        mtspr 256, r2
        blr

llvm-svn: 27352
2006-04-02 05:30:25 +00:00
Chris Lattner 70ec96fa32 Adjust to change in Intrinsics.gen interface.
llvm-svn: 27344
2006-04-02 03:35:01 +00:00
Chris Lattner 1b2436a624 add valuemapper support for inline asm
llvm-svn: 27332
2006-04-01 23:17:11 +00:00
Chris Lattner 6cf4914fd4 Fix InstCombine/2006-04-01-InfLoop.ll
llvm-svn: 27330
2006-04-01 22:05:01 +00:00
Chris Lattner dcd0792622 Fold A^(B&A) -> (B&A)^A
Fold (B&A)^A == ~B & A

This implements InstCombine/xor.ll:test2[56]

llvm-svn: 27328
2006-04-01 08:03:55 +00:00
Chris Lattner 8d1d8d364c If we can look through vector operations to find the scalar version of an
extract_element'd value, do so.

llvm-svn: 27323
2006-03-31 23:01:56 +00:00
Chris Lattner 92346c315e extractelement(undef,x) -> undef
llvm-svn: 27300
2006-03-31 18:25:14 +00:00
Chris Lattner 612fa8e6f3 Fix Transforms/InstCombine/2006-03-30-ExtractElement.ll
llvm-svn: 27261
2006-03-30 22:02:40 +00:00
Chris Lattner 42e0ba09aa teach the inliner to work with packed constants
llvm-svn: 27161
2006-03-27 05:50:18 +00:00
Chris Lattner d70d9f5b24 Don't crash on packed logical ops
llvm-svn: 27125
2006-03-25 21:58:26 +00:00
Chris Lattner f365f5f0c1 Fix spello
llvm-svn: 27052
2006-03-24 07:14:34 +00:00
Chris Lattner 5821a6a17a add the actual cost to the debug info
llvm-svn: 27051
2006-03-24 07:14:00 +00:00
Jim Laskey 8f64426f5c Strip changes to llvm.dbg intrinsics.
llvm-svn: 26993
2006-03-23 18:11:33 +00:00
Jim Laskey 83f99115db Can't combine anymore - we don't have a chain through llvm.dbg intrinsics.
llvm-svn: 26992
2006-03-23 18:10:42 +00:00
Chris Lattner 7d80b4f366 silence a bogus gcc warning
llvm-svn: 26953
2006-03-22 17:27:24 +00:00
Chris Lattner d783c76c18 Teach cee to propagate through switch statements. This implements
Transforms/CorrelatedExprs/switch.ll

Patch contributed by Eric Kidd!

llvm-svn: 26872
2006-03-19 19:37:24 +00:00
Evan Cheng c28282bd87 - Fixed a bogus if condition.
- Added more debugging info.
- Allow reuse of IV of negative stride. e.g. -4 stride == 2 * iv of -2 stride.

llvm-svn: 26841
2006-03-18 08:03:12 +00:00
Evan Cheng f09f0ebd48 Sort StrideOrder so we can process the smallest strides first. This allows
for more IV reuses.

llvm-svn: 26837
2006-03-18 00:44:49 +00:00
Evan Cheng 4520698820 Allow users of iv / stride to be rewritten with expression that is a multiply
of a smaller stride even if they have a common loop invariant expression part.

llvm-svn: 26828
2006-03-17 19:52:23 +00:00
Evan Cheng 3df447d354 For each loop, keep track of all the IV expressions inserted indexed by
stride. For a set of uses of the IV of a stride which is a multiple
of another stride, do not insert a new IV expression. Rather, reuse the
previous IV and rewrite the uses as uses of IV expression multiplied by
the factor.

e.g.
x = 0 ...; x ++
y = 0 ...; y += 4
then use of y can be rewritten as use of 4*x for x86.

llvm-svn: 26803
2006-03-16 21:53:05 +00:00