[AMDGPU] Preliminary patch for divergence driven instruction selection. Immediate selection predicate changed
Differential revision: https://reviews.llvm.org/D51734
Reviewers: rampitec
llvm-svn: 341928
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
index c95776d..d689d92 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
@@ -101,7 +101,7 @@
std::pair<SDValue, SDValue> foldFrameIndex(SDValue N) const;
bool isNoNanSrc(SDValue N) const;
bool isInlineImmediate(const SDNode *N) const;
-
+ bool isVGPRImm(const SDNode *N) const;
bool isUniformBr(const SDNode *N) const;
MachineSDNode *buildSMovImm64(SDLoc &DL, uint64_t Val, EVT VT) const;
@@ -2068,6 +2068,56 @@
return isExtractHiElt(In, Src);
}
+bool AMDGPUDAGToDAGISel::isVGPRImm(const SDNode * N) const {
+ if (Subtarget->getGeneration() < AMDGPUSubtarget::SOUTHERN_ISLANDS) {
+ return false;
+ }
+ const SIRegisterInfo *SIRI =
+ static_cast<const SIRegisterInfo *>(Subtarget->getRegisterInfo());
+ const SIInstrInfo * SII =
+ static_cast<const SIInstrInfo *>(Subtarget->getInstrInfo());
+
+ unsigned Limit = 0;
+ bool AllUsesAcceptSReg = true;
+ for (SDNode::use_iterator U = N->use_begin(), E = SDNode::use_end();
+ Limit < 10 && U != E; ++U, ++Limit) {
+ const TargetRegisterClass *RC = getOperandRegClass(*U, U.getOperandNo());
+
+ // If the register class is unknown, it could be an unknown
+ // register class that needs to be an SGPR, e.g. an inline asm
+ // constraint
+ if (!RC || SIRI->isSGPRClass(RC))
+ return false;
+
+ if (RC != &AMDGPU::VS_32RegClass) {
+ AllUsesAcceptSReg = false;
+ SDNode * User = *U;
+ if (User->isMachineOpcode()) {
+ unsigned Opc = User->getMachineOpcode();
+ MCInstrDesc Desc = SII->get(Opc);
+ if (Desc.isCommutable()) {
+ unsigned OpIdx = Desc.getNumDefs() + U.getOperandNo();
+ unsigned CommuteIdx1 = TargetInstrInfo::CommuteAnyOperandIndex;
+ if (SII->findCommutedOpIndices(Desc, OpIdx, CommuteIdx1)) {
+ unsigned CommutedOpNo = CommuteIdx1 - Desc.getNumDefs();
+ const TargetRegisterClass *CommutedRC = getOperandRegClass(*U, CommutedOpNo);
+ if (CommutedRC == &AMDGPU::VS_32RegClass)
+ AllUsesAcceptSReg = true;
+ }
+ }
+ }
+ // If "AllUsesAcceptSReg == false" so far we haven't suceeded
+ // commuting current user. This means have at least one use
+ // that strictly require VGPR. Thus, we will not attempt to commute
+ // other user instructions.
+ if (!AllUsesAcceptSReg)
+ break;
+ }
+ }
+ return !AllUsesAcceptSReg && (Limit < 10);
+}
+
+
void AMDGPUDAGToDAGISel::PostprocessISelDAG() {
const AMDGPUTargetLowering& Lowering =
*static_cast<const AMDGPUTargetLowering*>(getTargetLowering());