Check shouldReduceLoadWidth from SimplifySetCC
SimplifySetCC could shrink a load without checking for
profitability or legality of such shink with a target.
Added checks to prevent shrinking of aligned scalar loads
in AMDGPU below dword as scalar engine does not support it.
Differential Revision: https://reviews.llvm.org/D53846
llvm-svn: 345778
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index a1b9198..9823dd7 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -667,6 +667,18 @@
EVT OldVT = N->getValueType(0);
unsigned OldSize = OldVT.getStoreSizeInBits();
+ MemSDNode *MN = cast<MemSDNode>(N);
+ unsigned AS = MN->getAddressSpace();
+ // Do not shrink an aligned scalar load to sub-dword.
+ // Scalar engine cannot do sub-dword loads.
+ if (OldSize >= 32 && NewSize < 32 && MN->getAlignment() >= 4 &&
+ (AS == AMDGPUAS::CONSTANT_ADDRESS ||
+ AS == AMDGPUAS::CONSTANT_ADDRESS_32BIT ||
+ (isa<LoadSDNode>(N) &&
+ AS == AMDGPUAS::GLOBAL_ADDRESS && MN->isInvariant())) &&
+ AMDGPUInstrInfo::isUniformMMO(MN->getMemOperand()))
+ return false;
+
// Don't produce extloads from sub 32-bit types. SI doesn't have scalar
// extloads, so doing one requires using a buffer_load. In cases where we
// still couldn't use a scalar load, using the wider load shouldn't really