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| author | Bill Schmidt <wschmidt@linux.vnet.ibm.com> | 2014-05-27 15:57:51 +0000 |
|---|---|---|
| committer | Bill Schmidt <wschmidt@linux.vnet.ibm.com> | 2014-05-27 15:57:51 +0000 |
| commit | 3f01f5296ec2d146f92bcc479a5bade9e898fc40 (patch) | |
| tree | 49fd56349563075e6e8deb968aff93337a87565c /test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll | |
| parent | 61e341e0bfcc83ec865fe763759e66ab3c2feba5 (diff) | |
| download | llvm-3f01f5296ec2d146f92bcc479a5bade9e898fc40.tar.gz llvm-3f01f5296ec2d146f92bcc479a5bade9e898fc40.tar.bz2 llvm-3f01f5296ec2d146f92bcc479a5bade9e898fc40.tar.xz | |
[PATCH] Correct type used for VADD_SPLAT optimization on PowerPC
In PPCISelLowering.cpp: PPCTargetLowering::LowerBUILD_VECTOR(), there
is an optimization for certain patterns to generate one or two vector
splats followed by a vector add or subtract. This operation is
represented by a VADD_SPLAT in the selection DAG. Prior to this
patch, it was possible for the VADD_SPLAT to be assigned the wrong
data type, causing incorrect code generation. This patch corrects the
problem.
Specifically, the code previously assigned the value type of the
BUILD_VECTOR node to the newly generated VADD_SPLAT node. This is
correct much of the time, but not always. The problem is that the
call to isConstantSplat() may return a SplatBitSize that is not the
same as the number of bits in the original element vector type. The
correct type to assign is a vector type with the same element bit size
as SplatBitSize.
The included test case shows an example of this, where the
BUILD_VECTOR node has a type of v16i8. The vector to be built is {0,
16, 0, 16, 0, 16, 0, 16, 0, 16, 0, 16, 0, 16, 0, 16}. isConstantSplat
detects that we can generate a splat of 16 for type v8i16, which is
the type we must assign to the VADD_SPLAT node. If we do not, we
generate a vspltisb of 8 and a vaddubm, which generates the incorrect
result {16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
16}. The correct code generation is a vspltish of 8 and a vadduhm.
This patch also corrected code generation for
CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll, which had been marked
as an XFAIL, so we can remove the XFAIL from the test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209662 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll')
| -rw-r--r-- | test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll b/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll index 00a402e0e4..8802b97d2a 100644 --- a/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll +++ b/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll @@ -1,6 +1,5 @@ ; RUN: llc < %s -march=ppc32 -mcpu=g5 | grep vadduhm ; RUN: llc < %s -march=ppc32 -mcpu=g5 | grep vsubuhm -; XFAIL: * define <4 x i32> @test() nounwind { ret <4 x i32> < i32 4293066722, i32 4293066722, i32 4293066722, i32 4293066722> |