Skip to content

[EXTERNAL] Cherry pick fix for const folding of immediate args #1939

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Aug 8, 2025
Merged

[EXTERNAL] Cherry pick fix for const folding of immediate args #1939

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5044dd4
[EXTERNAL] Cherry-pick https://github.com/llvm/llvm-project/pull/148205
umangyadav Aug 7, 2025
07ba94d
Merge branch 'develop' into constFoldPatch
umangyadav Aug 7, 2025
9983a40
add test to ensure compilation passes
umangyadav Aug 8, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 9 additions & 3 deletions external/llvm-project/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1657,6 +1657,7 @@ bool SIFoldOperandsImpl::foldInstOperand(MachineInstr &MI,
for (MachineInstr *Copy : CopiesToReplace)
Copy->addImplicitDefUseOperands(*MF);

SetVector<MachineInstr *> ConstantFoldCandidates;
for (FoldCandidate &Fold : FoldList) {
assert(!Fold.isReg() || Fold.OpToFold);
if (Fold.isReg() && Fold.OpToFold->getReg().isVirtual()) {
Expand All @@ -1679,16 +1680,21 @@ bool SIFoldOperandsImpl::foldInstOperand(MachineInstr &MI,
<< static_cast<int>(Fold.UseOpNo) << " of "
<< *Fold.UseMI);

if (Fold.isImm() && tryConstantFoldOp(Fold.UseMI)) {
LLVM_DEBUG(dbgs() << "Constant folded " << *Fold.UseMI);
Changed = true;
if (Fold.isImm()) {
ConstantFoldCandidates.insert(Fold.UseMI);
}

} else if (Fold.Commuted) {
// Restoring instruction's original operand order if fold has failed.
TII->commuteInstruction(*Fold.UseMI, false);
}
}
for (MachineInstr *MI : ConstantFoldCandidates) {
if (tryConstantFoldOp(MI)) {
LLVM_DEBUG(dbgs() << "Constant folded " << *MI);
Changed = true;
}
}
return true;
}

Expand Down
15 changes: 15 additions & 0 deletions external/llvm-project/llvm/test/CodeGen/AMDGPU/bug-multi-operands-to-update-after-fold.mir
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
# RUN: llc -mtriple=amdgcn-amd-hsa -mcpu=gfx1031 -run-pass=si-fold-operands -o - %s | FileCheck %s
---
name: snork
body: |
bb.0:
; CHECK-LABEL: name: snork
; CHECK: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 0
; CHECK-NEXT: [[REG_SEQUENCE:%[0-9]+]]:sgpr_128 = REG_SEQUENCE [[S_MOV_B32_]], %subreg.sub0, [[S_MOV_B32_]], %subreg.sub1, [[S_MOV_B32_]], %subreg.sub2, [[S_MOV_B32_]], %subreg.sub3
; CHECK-NEXT: SI_RETURN
%0:sreg_32 = S_MOV_B32 0
%1:sgpr_128 = REG_SEQUENCE %0, %subreg.sub0, %0, %subreg.sub1, %0, %subreg.sub2, %0, %subreg.sub3
%2:sreg_32 = S_OR_B32 %1.sub0, %1.sub3, implicit-def dead $scc
SI_RETURN
...