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[SPIR-V] Ensure that cleaning of temporary constants doesn't purge tracked constants #95303

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merged 2 commits into from
Jun 13, 2024
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[SPIR-V] Ensure that cleaning of temporary constants doesn't purge tracked constants #95303

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da30d72
ensure that cleaning of temporary constants doesn't purge tracked ones
VyacheslavLevytskyy Jun 12, 2024
19300d1
tweak and format
VyacheslavLevytskyy Jun 12, 2024
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17 changes: 12 additions & 5 deletions llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,8 @@ class SPIRVPreLegalizer : public MachineFunctionPass {
static void
addConstantsToTrack(MachineFunction &MF, SPIRVGlobalRegistry *GR,
const SPIRVSubtarget &STI,
DenseMap<MachineInstr *, Type *> &TargetExtConstTypes) {
DenseMap<MachineInstr *, Type *> &TargetExtConstTypes,
SmallSet<Register, 4> &TrackedConstRegs) {
MachineRegisterInfo &MRI = MF.getRegInfo();
DenseMap<MachineInstr *, Register> RegsAlreadyAddedToDT;
SmallVector<MachineInstr *, 10> ToErase, ToEraseComposites;
Expand Down Expand Up @@ -80,6 +81,7 @@ addConstantsToTrack(MachineFunction &MF, SPIRVGlobalRegistry *GR,
}
}
GR->add(Const, &MF, SrcReg);
TrackedConstRegs.insert(SrcReg);
if (Const->getType()->isTargetExtTy()) {
// remember association so that we can restore it when assign types
MachineInstr *SrcMI = MRI.getVRegDef(SrcReg);
Expand Down Expand Up @@ -121,7 +123,9 @@ addConstantsToTrack(MachineFunction &MF, SPIRVGlobalRegistry *GR,
MI->eraseFromParent();
}

static void foldConstantsIntoIntrinsics(MachineFunction &MF) {
static void
foldConstantsIntoIntrinsics(MachineFunction &MF,
const SmallSet<Register, 4> &TrackedConstRegs) {
SmallVector<MachineInstr *, 10> ToErase;
MachineRegisterInfo &MRI = MF.getRegInfo();
const unsigned AssignNameOperandShift = 2;
Expand All @@ -137,7 +141,8 @@ static void foldConstantsIntoIntrinsics(MachineFunction &MF) {
MI.removeOperand(NumOp);
MI.addOperand(MachineOperand::CreateImm(
ConstMI->getOperand(1).getCImm()->getZExtValue()));
if (MRI.use_empty(ConstMI->getOperand(0).getReg()))
Register DefReg = ConstMI->getOperand(0).getReg();
if (MRI.use_empty(DefReg) && !TrackedConstRegs.contains(DefReg))
ToErase.push_back(ConstMI);
}
}
Expand Down Expand Up @@ -836,8 +841,10 @@ bool SPIRVPreLegalizer::runOnMachineFunction(MachineFunction &MF) {
MachineIRBuilder MIB(MF);
// a registry of target extension constants
DenseMap<MachineInstr *, Type *> TargetExtConstTypes;
addConstantsToTrack(MF, GR, ST, TargetExtConstTypes);
foldConstantsIntoIntrinsics(MF);
// to keep record of tracked constants
SmallSet<Register, 4> TrackedConstRegs;
addConstantsToTrack(MF, GR, ST, TargetExtConstTypes, TrackedConstRegs);
foldConstantsIntoIntrinsics(MF, TrackedConstRegs);
insertBitcasts(MF, GR, MIB);
generateAssignInstrs(MF, GR, MIB, TargetExtConstTypes);
processSwitches(MF, GR, MIB);
Expand Down
25 changes: 25 additions & 0 deletions llvm/test/CodeGen/SPIRV/keep-tracked-const.ll
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@@ -0,0 +1,25 @@
; This test case ensures that cleaning of temporary constants doesn't purge tracked ones.

; RUN: llc -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s --check-prefix=CHECK-SPIRV
; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}

; CHECK-SPIRV: %[[#Int:]] = OpTypeInt 32 0
; CHECK-SPIRV: %[[#C0:]] = OpConstant %[[#Int]] 0
; CHECK-SPIRV: %[[#C1:]] = OpConstant %[[#Int]] 1
; CHECK-SPIRV: OpSelect %[[#Int]] %[[#]] %[[#C1]] %[[#C0]]


define spir_kernel void @foo() {
entry:
%addr = alloca i32
%r1 = call i8 @_Z20__spirv_SpecConstantia(i32 0, i8 1)
; The name '%conv17.i' is important for the test case,
; because it includes i32 0 when encoded for SPIR-V usage.
%conv17.i = sext i8 %r1 to i64
%tobool = trunc i8 %r1 to i1
%r2 = zext i1 %tobool to i32
store i32 %r2, ptr %addr
ret void
}

declare i8 @_Z20__spirv_SpecConstantia(i32, i8)
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