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| author | Hal Finkel <hfinkel@anl.gov> | 2015-09-03 21:12:15 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2015-09-03 21:12:15 +0000 |
| commit | 99d95328d6af9b99a607aec6ece9a950c38c8913 (patch) | |
| tree | 3c12e64e441eb723eb7f8a620135e33914c16e69 /llvm | |
| parent | c079df09a6c38a88ee4f921857682413350ff734 (diff) | |
| download | bcm5719-llvm-99d95328d6af9b99a607aec6ece9a950c38c8913.tar.gz bcm5719-llvm-99d95328d6af9b99a607aec6ece9a950c38c8913.zip | |
[PowerPC] Compute the MMO offset for an unaligned load with signed arithmetic
If you compute the MMO offset using unsigned arithmetic, you end up with a
large positive offset instead of a small negative one. In theory, this could
cause bad instruction-scheduling decisions later.
I noticed this by inspection from the debug output, and using that for the
regression test is the best I can do right now.
llvm-svn: 246805
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Target/PowerPC/PPCISelLowering.cpp | 3 | ||||
| -rw-r--r-- | llvm/test/CodeGen/PowerPC/unal-vec-negarith.ll | 17 |
2 files changed, 19 insertions, 1 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp index 40a80d62113..116ecb4537e 100644 --- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp +++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp @@ -10302,7 +10302,8 @@ SDValue PPCTargetLowering::PerformDAGCombine(SDNode *N, // original unaligned load. MachineFunction &MF = DAG.getMachineFunction(); MachineMemOperand *BaseMMO = - MF.getMachineMemOperand(LD->getMemOperand(), -MemVT.getStoreSize()+1, + MF.getMachineMemOperand(LD->getMemOperand(), + -(long)MemVT.getStoreSize()+1, 2*MemVT.getStoreSize()-1); // Create the new base load. diff --git a/llvm/test/CodeGen/PowerPC/unal-vec-negarith.ll b/llvm/test/CodeGen/PowerPC/unal-vec-negarith.ll new file mode 100644 index 00000000000..faac891f5c6 --- /dev/null +++ b/llvm/test/CodeGen/PowerPC/unal-vec-negarith.ll @@ -0,0 +1,17 @@ +; RUN: llc -debug-only=isel <%s >%t 2>&1 && FileCheck <%t %s +; REQUIRES: asserts + +target datalayout = "E-m:e-i64:64-n32:64" +target triple = "powerpc64-unknown-linux-gnu" + +define <16 x i8> @test_l_v16i8(<16 x i8>* %p) #0 { +entry: + %r = load <16 x i8>, <16 x i8>* %p, align 1 + ret <16 x i8> %r + +; CHECK-NOT: v4i32,ch = llvm.ppc.altivec.lvx{{.*}}<LD31[%p+4294967281](align=1)> +; CHECK: v4i32,ch = llvm.ppc.altivec.lvx{{.*}}<LD31[%p+-15](align=1)> +} + +attributes #0 = { nounwind "target-cpu"="pwr7" } + |
