Rmys
86 lines
3.7 KiB
Diff
86 lines
3.7 KiB
Diff
commit b08a140a8fe8d0b0d16a93042b4952d6e34ab913
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Author: Piotr Sobczak <Piotr.Sobczak@amd.com>
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Date: Wed Jan 27 16:02:49 2021 +0100
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[AMDGPU] Avoid an illegal operand in si-shrink-instructions
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Before the patch it was possible to trigger a constant bus
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violation when folding immediates into a shrunk instruction.
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The patch adds a check to enforce the legality of the new operand.
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Differential Revision: https://reviews.llvm.org/D95527
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diff --git a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
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index 9c6833a7dab6..6c1b16eddc84 100644
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--- a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
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+++ b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
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@@ -84,21 +84,23 @@ static bool foldImmediates(MachineInstr &MI, const SIInstrInfo *TII,
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MachineOperand &MovSrc = Def->getOperand(1);
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bool ConstantFolded = false;
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- if (MovSrc.isImm() && (isInt<32>(MovSrc.getImm()) ||
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- isUInt<32>(MovSrc.getImm()))) {
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- // It's possible to have only one component of a super-reg defined by
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- // a single mov, so we need to clear any subregister flag.
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- Src0.setSubReg(0);
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- Src0.ChangeToImmediate(MovSrc.getImm());
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- ConstantFolded = true;
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- } else if (MovSrc.isFI()) {
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- Src0.setSubReg(0);
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- Src0.ChangeToFrameIndex(MovSrc.getIndex());
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- ConstantFolded = true;
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- } else if (MovSrc.isGlobal()) {
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- Src0.ChangeToGA(MovSrc.getGlobal(), MovSrc.getOffset(),
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- MovSrc.getTargetFlags());
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- ConstantFolded = true;
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+ if (TII->isOperandLegal(MI, Src0Idx, &MovSrc)) {
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+ if (MovSrc.isImm() &&
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+ (isInt<32>(MovSrc.getImm()) || isUInt<32>(MovSrc.getImm()))) {
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+ // It's possible to have only one component of a super-reg defined
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+ // by a single mov, so we need to clear any subregister flag.
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+ Src0.setSubReg(0);
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+ Src0.ChangeToImmediate(MovSrc.getImm());
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+ ConstantFolded = true;
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+ } else if (MovSrc.isFI()) {
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+ Src0.setSubReg(0);
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+ Src0.ChangeToFrameIndex(MovSrc.getIndex());
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+ ConstantFolded = true;
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+ } else if (MovSrc.isGlobal()) {
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+ Src0.ChangeToGA(MovSrc.getGlobal(), MovSrc.getOffset(),
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+ MovSrc.getTargetFlags());
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+ ConstantFolded = true;
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+ }
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}
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if (ConstantFolded) {
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diff --git a/llvm/test/CodeGen/AMDGPU/shrink-instructions-illegal-fold.mir b/llvm/test/CodeGen/AMDGPU/shrink-instructions-illegal-fold.mir
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new file mode 100644
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index 000000000000..7889f437facf
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--- /dev/null
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+++ b/llvm/test/CodeGen/AMDGPU/shrink-instructions-illegal-fold.mir
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@@ -0,0 +1,23 @@
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+# RUN: llc -march=amdgcn -mcpu=gfx900 -run-pass=si-shrink-instructions --verify-machineinstrs %s -o - | FileCheck %s
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+
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+# Make sure immediate folding into V_CNDMASK respects constant bus restrictions.
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+---
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+
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+name: shrink_cndmask_illegal_imm_folding
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+tracksRegLiveness: true
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+body: |
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+ bb.0:
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+ liveins: $vgpr0, $vgpr1
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+ ; CHECK-LABEL: name: shrink_cndmask_illegal_imm_folding
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+ ; CHECK: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
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+ ; CHECK: [[MOV:%[0-9]+]]:vgpr_32 = V_MOV_B32_e32 32768, implicit $exec
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+ ; CHECK: V_CMP_EQ_U32_e32 0, [[COPY]], implicit-def $vcc, implicit $exec
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+ ; CHECK: V_CNDMASK_B32_e32 [[MOV]], killed [[COPY]], implicit $vcc, implicit $exec
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+
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+ %0:vgpr_32 = COPY $vgpr0
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+ %1:vgpr_32 = V_MOV_B32_e32 32768, implicit $exec
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+ V_CMP_EQ_U32_e32 0, %0:vgpr_32, implicit-def $vcc, implicit $exec
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+ %2:vgpr_32 = V_CNDMASK_B32_e64 0, %1:vgpr_32, 0, killed %0:vgpr_32, $vcc, implicit $exec
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+ S_NOP 0
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+
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+...
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