[llvm] r359351 - [GlobalISel][AArch64] Use getConstantVRegValWithLookThrough for extracts
Jessica Paquette via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 26 14:53:13 PDT 2019
Author: paquette
Date: Fri Apr 26 14:53:13 2019
New Revision: 359351
URL: http://llvm.org/viewvc/llvm-project?rev=359351&view=rev
Log:
[GlobalISel][AArch64] Use getConstantVRegValWithLookThrough for extracts
getConstantVRegValWithLookThrough does the same thing as the
getConstantValueForReg function, and has more visibility across GISel. Plus, it
supports looking through G_TRUNC, G_SEXT, and G_ZEXT. So, we get better code
reuse and more functionality for free by using it.
Add some test cases to select-extract-vector-elt.mir to show that we can now
look through those instructions.
Modified:
llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp
llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-extract-vector-elt.mir
Modified: llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp?rev=359351&r1=359350&r2=359351&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp Fri Apr 26 14:53:13 2019
@@ -2288,40 +2288,6 @@ static bool getLaneCopyOpcode(unsigned &
return true;
}
-/// Given a register \p Reg, find the value of a constant defining \p Reg.
-/// Return true if one could be found, and store it in \p Val. Return false
-/// otherwise.
-static bool getConstantValueForReg(unsigned Reg, MachineRegisterInfo &MRI,
- unsigned &Val) {
- // Look at the def of the register.
- MachineInstr *Def = MRI.getVRegDef(Reg);
- if (!Def)
- return false;
-
- // Find the first definition which isn't a copy.
- if (Def->isCopy()) {
- Reg = Def->getOperand(1).getReg();
- auto It = find_if_not(MRI.reg_nodbg_instructions(Reg),
- [](const MachineInstr &MI) { return MI.isCopy(); });
- if (It == MRI.reg_instr_nodbg_end()) {
- LLVM_DEBUG(dbgs() << "Couldn't find non-copy def for register\n");
- return false;
- }
- Def = &*It;
- }
-
- // TODO: Handle opcodes other than G_CONSTANT.
- if (Def->getOpcode() != TargetOpcode::G_CONSTANT) {
- LLVM_DEBUG(dbgs() << "VRegs defined by anything other than G_CONSTANT "
- "currently unsupported.\n");
- return false;
- }
-
- // Return the constant value associated with the operand.
- Val = Def->getOperand(1).getCImm()->getLimitedValue();
- return true;
-}
-
MachineInstr *AArch64InstructionSelector::emitExtractVectorElt(
Optional<unsigned> DstReg, const RegisterBank &DstRB, LLT ScalarTy,
unsigned VecReg, unsigned LaneIdx, MachineIRBuilder &MIRBuilder) const {
@@ -2405,9 +2371,10 @@ bool AArch64InstructionSelector::selectE
}
// Find the index to extract from.
- unsigned LaneIdx = 0;
- if (!getConstantValueForReg(LaneIdxOp.getReg(), MRI, LaneIdx))
+ auto VRegAndVal = getConstantVRegValWithLookThrough(LaneIdxOp.getReg(), MRI);
+ if (!VRegAndVal)
return false;
+ unsigned LaneIdx = VRegAndVal->Value;
MachineIRBuilder MIRBuilder(I);
@@ -2983,9 +2950,10 @@ bool AArch64InstructionSelector::selectI
// Find the definition of the index. Bail out if it's not defined by a
// G_CONSTANT.
unsigned IdxReg = I.getOperand(3).getReg();
- unsigned LaneIdx = 0;
- if (!getConstantValueForReg(IdxReg, MRI, LaneIdx))
+ auto VRegAndVal = getConstantVRegValWithLookThrough(IdxReg, MRI);
+ if (!VRegAndVal)
return false;
+ unsigned LaneIdx = VRegAndVal->Value;
// Perform the lane insert.
unsigned SrcReg = I.getOperand(1).getReg();
Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-extract-vector-elt.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-extract-vector-elt.mir?rev=359351&r1=359350&r2=359351&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-extract-vector-elt.mir (original)
+++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-extract-vector-elt.mir Fri Apr 26 14:53:13 2019
@@ -138,3 +138,74 @@ body: |
RET_ReallyLR implicit $h0
...
+---
+name: v8s16_fpr_zext
+alignment: 2
+legalized: true
+regBankSelected: true
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $q0
+ ; CHECK-LABEL: name: v8s16_fpr_zext
+ ; CHECK: liveins: $q0
+ ; CHECK: [[COPY:%[0-9]+]]:fpr128 = COPY $q0
+ ; CHECK: [[CPYi16_:%[0-9]+]]:fpr16 = CPYi16 [[COPY]], 1
+ ; CHECK: $h0 = COPY [[CPYi16_]]
+ ; CHECK: RET_ReallyLR implicit $h0
+ %0:fpr(<8 x s16>) = COPY $q0
+ %1:gpr(s32) = G_CONSTANT i32 1
+ %2:gpr(s64) = G_ZEXT %1
+ %3:fpr(s64) = COPY %2(s64)
+ %4:fpr(s16) = G_EXTRACT_VECTOR_ELT %0(<8 x s16>), %3(s64)
+ $h0 = COPY %4(s16)
+ RET_ReallyLR implicit $h0
+
+...
+---
+name: v8s16_fpr_sext
+alignment: 2
+legalized: true
+regBankSelected: true
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $q0
+ ; CHECK-LABEL: name: v8s16_fpr_sext
+ ; CHECK: liveins: $q0
+ ; CHECK: [[COPY:%[0-9]+]]:fpr128 = COPY $q0
+ ; CHECK: [[CPYi16_:%[0-9]+]]:fpr16 = CPYi16 [[COPY]], 1
+ ; CHECK: $h0 = COPY [[CPYi16_]]
+ ; CHECK: RET_ReallyLR implicit $h0
+ %0:fpr(<8 x s16>) = COPY $q0
+ %1:gpr(s32) = G_CONSTANT i32 1
+ %2:gpr(s64) = G_SEXT %1
+ %3:fpr(s64) = COPY %2(s64)
+ %4:fpr(s16) = G_EXTRACT_VECTOR_ELT %0(<8 x s16>), %3(s64)
+ $h0 = COPY %4(s16)
+ RET_ReallyLR implicit $h0
+
+...
+---
+name: v8s16_fpr_trunc
+alignment: 2
+legalized: true
+regBankSelected: true
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $q0
+ ; CHECK-LABEL: name: v8s16_fpr_trunc
+ ; CHECK: liveins: $q0
+ ; CHECK: [[COPY:%[0-9]+]]:fpr128 = COPY $q0
+ ; CHECK: [[CPYi16_:%[0-9]+]]:fpr16 = CPYi16 [[COPY]], 1
+ ; CHECK: $h0 = COPY [[CPYi16_]]
+ ; CHECK: RET_ReallyLR implicit $h0
+ %0:fpr(<8 x s16>) = COPY $q0
+ %1:gpr(s64) = G_CONSTANT i64 1
+ %2:gpr(s32) = G_TRUNC %1
+ %3:gpr(s64) = G_SEXT %2
+ %4:fpr(s64) = COPY %3(s64)
+ %5:fpr(s16) = G_EXTRACT_VECTOR_ELT %0(<8 x s16>), %4(s64)
+ $h0 = COPY %5(s16)
+ RET_ReallyLR implicit $h0
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