-
Notifications
You must be signed in to change notification settings - Fork 10.8k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[CGP] Drop nneg flag when moving zext past instruction (#72103)
Fix the issue by not reusing the zext at all. The code already handles creation of new zexts if more than one is needed. Always use that code-path instead of trying to reuse the old zext in some case. (Alternatively we could also drop poison-generating flags on the old zext, but it seems cleaner to not reuse it at all, especially if it's not always possible anyway.) Fixes #72046.
- Loading branch information
Showing
5 changed files
with
35 additions
and
30 deletions.
There are no files selected for viewing
This file contains 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
This file contains 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
This file contains 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
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,19 @@ | ||
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3 | ||
; RUN: opt -S -codegenprepare -mtriple=x86_64-unknown-unknown < %s | FileCheck %s | ||
|
||
; Make sure the nneg flag is dropped when lshr and zext are interchanged. | ||
define i8 @get(ptr %box, i32 %in) { | ||
; CHECK-LABEL: define i8 @get( | ||
; CHECK-SAME: ptr [[BOX:%.*]], i32 [[IN:%.*]]) { | ||
; CHECK-NEXT: [[PROMOTED:%.*]] = zext i32 [[IN]] to i64 | ||
; CHECK-NEXT: [[SHR:%.*]] = lshr i64 [[PROMOTED]], 24 | ||
; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[BOX]], i64 [[SHR]] | ||
; CHECK-NEXT: [[RES:%.*]] = load i8, ptr [[ARRAYIDX]], align 1 | ||
; CHECK-NEXT: ret i8 [[RES]] | ||
; | ||
%shr = lshr i32 %in, 24 | ||
%idxprom = zext nneg i32 %shr to i64 | ||
%arrayidx = getelementptr inbounds i8, ptr %box, i64 %idxprom | ||
%res = load i8, ptr %arrayidx, align 1 | ||
ret i8 %res | ||
} |
This file contains 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
2 changes: 1 addition & 1 deletion
2
llvm/test/Transforms/CodeGenPrepare/X86/promoted-zext-debugloc.ll
This file contains 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