[TargetLowering][ARM][PowerPC] LHS and RHS should be frozen for 3-way compares #159993
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@llvm/pr-subscribers-backend-risc-v @llvm/pr-subscribers-backend-arm Author: AZero13 (AZero13) ChangesLHS and RHS are used multiple times. Full diff: https://github.com/llvm/llvm-project/pull/159993.diff 1 Files Affected:
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 9052cbfa89deb..9905a4457f35b 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -10479,6 +10479,9 @@ SDValue ARMTargetLowering::LowerCMP(SDValue Op, SelectionDAG &DAG) const {
// Special case for Thumb1 UCMP only
if (!IsSigned && Subtarget->isThumb1Only()) {
+ LHS = DAG.getFreeze(LHS);
+ RHS = DAG.getFreeze(RHS);
+
// For Thumb unsigned comparison, use this sequence:
// subs r2, r0, r1 ; r2 = LHS - RHS, sets flags
// sbc r2, r2 ; r2 = r2 - r2 - !carry
|
AZero13
force-pushed
the
undefs
branch
2 times, most recently
from
33b991e to
a3300f0
Compare
AZero13
changed the title
AZero13
changed the title
LHS and RHS are used multiple times.
arsenm
reviewed
Oct 11, 2025
There was a problem hiding this comment.
Alive doesn't seem to think this is necessary: https://alive2.llvm.org/ce/z/JLx9Rb
Wonder if I should remove it from the PowerPC ucmp then if true... I'll look into this tomorrow |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
LHS and RHS are used multiple times.