If we have the situation where a Swap feeds a Splat we can sometimes change the
index on the Splat and then remove the Swap instruction.
Fixed the test case that was failing and recommit after pulling the original
commit.
Original revision is here: https://reviews.llvm.org/D39009
llvm-svn: 316478
If we have the situation where a Swap feeds a Splat we can sometimes change the
index on the Splat and then remove the Swap instruction.
Differential Revision: https://reviews.llvm.org/D39009
llvm-svn: 316366
The commit at https://reviews.llvm.org/rL315888 is causing some failures
with internal testing. Disabling this code until we can resolve the issues.
llvm-svn: 316199
This patch enables redundant sign- and zero-extension elimination in PowerPC MI Peephole pass.
If the input value of a sign- or zero-extension is known to be already sign- or zero-extended, the operation is redundant and can be eliminated.
One common case is sign-extensions for a method parameter or for a method return value; they must be sign- or zero-extended as defined in PPC ELF ABI.
For example of the following simple code, two extsw instructions are generated before the invocation of int_func and before the return. With this patch, both extsw are eliminated.
void int_func(int);
void ii_test(int a) {
if (a & 1) return int_func(a);
}
Such redundant sign- or zero-extensions are quite common in many programs; e.g. I observed about 60,000 occurrences of the elimination while compiling the LLVM+CLANG.
Differential Revision: https://reviews.llvm.org/D31319
llvm-svn: 315888
The issue is that we assume operand zero of the input to the add instruction
is a register. In this case, the input comes from inline assembly and
operand zero is not a register thereby causing a crash.
The code will bail anyway if the input instruction doesn't have the right
opcode. So do that check first and let short-circuiting prevent the crash.
llvm-svn: 315285
This is a follow-on of D37211.
D37211 eliminates a compare instruction if two conditional branches can be made based on the one compare instruction, e.g.
if (a == 0) { ... }
else if (a < 0) { ... }
This patch extends this optimization to support partially redundant cases, which often happen in while loops.
For example, one compare instruction is moved from the loop body into the preheader by this optimization in the following example.
do {
if (a == 0) dummy1();
a = func(a);
} while (a > 0);
Differential Revision: https://reviews.llvm.org/D38236
llvm-svn: 314390
Two blocks prior to the join each perform an li and the the join block has an
add using the initialized register. Optimize each predecessor block to instead
use addi and delete the li's and add.
Differential Revision: https://reviews.llvm.org/D36734
llvm-svn: 313639
If multiple conditional branches are executed based on the same comparison, we can execute multiple conditional branches based on the result of one comparison on PPC. For example,
if (a == 0) { ... }
else if (a < 0) { ... }
can be executed by one compare and two conditional branches instead of two pairs of a compare and a conditional branch.
This patch identifies a code sequence of the two pairs of a compare and a conditional branch and merge the compares if possible.
To maximize the opportunity, we do canonicalization of code sequence before merging compares.
For the above example, the input for this pass looks like:
cmplwi r3, 0
beq 0, .LBB0_3
cmpwi r3, -1
bgt 0, .LBB0_4
So, before merging two compares, we canonicalize it as
cmpwi r3, 0 ; cmplwi and cmpwi yield same result for beq
beq 0, .LBB0_3
cmpwi r3, 0 ; greather than -1 means greater or equal to 0
bge 0, .LBB0_4
The generated code should be
cmpwi r3, 0
beq 0, .LBB0_3
bge 0, .LBB0_4
Differential Revision: https://reviews.llvm.org/D37211
llvm-svn: 312514
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
Rename from addOperand to just add, to match the other method that has been
added to MachineInstrBuilder for adding more than just 1 operand.
See https://reviews.llvm.org/D28057 for the whole discussion.
Differential Revision: https://reviews.llvm.org/D28556
llvm-svn: 291891
This is the final patch in the series of patches that improves
BUILD_VECTOR handling on PowerPC. This adds a few peephole optimizations
to remove redundant instructions. It also adds a large test case which
encompasses a large set of code patterns that build vectors - this test
case was the motivator for this series of patches.
Differential Revision: https://reviews.llvm.org/D26066
llvm-svn: 288800
Summary:
In PPCMIPeephole, when we see two splat instructions, we can't simply do the following transformation:
B = Splat A
C = Splat B
=>
C = Splat A
because B may still be used between these two instructions. Instead, we should make the second Splat a PPC::COPY and let later passes decide whether to remove it or not:
B = Splat A
C = Splat B
=>
B = Splat A
C = COPY B
Fixes PR30663.
Reviewers: echristo, iteratee, kbarton, nemanjai
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D25493
llvm-svn: 283961
This patch corresponds to review:
https://reviews.llvm.org/D23155
This patch removes the VSHRC register class (based on D20310) and adds
exploitation of the Power9 sub-word integer loads into VSX registers as well
as vector sign extensions.
The new instructions are useful for a few purposes:
Int to Fp conversions of 1 or 2-byte values loaded from memory
Building vectors of 1 or 2-byte integers with values loaded from memory
Storing individual 1 or 2-byte elements from integer vectors
This patch implements all of those uses.
llvm-svn: 283190
This patch adds a pass for doing PowerPC peephole optimizations at the
MI level while the code is still in SSA form. This allows for easy
modifications to the instructions while depending on a subsequent pass
of DCE. Both passes are very fast due to the characteristics of SSA.
At this time, the only peepholes added are for cleaning up various
redundancies involving the XXPERMDI instruction. However, I would
expect this will be a useful place to add more peepholes for
inefficiencies generated during instruction selection. The pass is
placed after VSX swap optimization, as it is best to let that pass
remove unnecessary swaps before performing any remaining clean-ups.
The utility of these clean-ups are demonstrated by changes to four
existing test cases, all of which now have tighter expected code
generation. I've also added Eric Schweiz's bugpoint-reduced test from
PR25157, for which we now generate tight code. One other test started
failing for me, and I've fixed it
(test/Transforms/PlaceSafepoints/finite-loops.ll) as well; this is not
related to my changes, and I'm not sure why it works before and not
after. The problem is that the CHECK-NOT: of "statepoint" from test1
fails because of the "statepoint" in test2, and so forth. Adding a
CHECK-LABEL in between keeps the different occurrences of that string
properly scoped.
llvm-svn: 252651
Stefan Pintilie