Skip to content

[InstCombine] Handle commuted patterns in foldSelectWithSRem #121896

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 2 commits into from
Jan 7, 2025
Merged

[InstCombine] Handle commuted patterns in foldSelectWithSRem #121896

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
8c7a4f4
[InstCombine] Add pre-commit tests. NFC.
dtcxzyw Jan 7, 2025
d5fb515
[InstCombine] Handle commuted patterns in `foldSelectWithSRem`
dtcxzyw Jan 7, 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
4 changes: 2 additions & 2 deletions llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2823,9 +2823,9 @@ static Instruction *foldSelectWithSRem(SelectInst &SI, InstCombinerImpl &IC,
// %cnd = icmp slt i32 %rem, 0
// %add = add i32 %rem, %n
// %sel = select i1 %cnd, i32 %add, i32 %rem
if (match(TrueVal, m_Add(m_Specific(RemRes), m_Value(Remainder))) &&
if (match(TrueVal, m_c_Add(m_Specific(RemRes), m_Value(Remainder))) &&
match(RemRes, m_SRem(m_Value(Op), m_Specific(Remainder))) &&
IC.isKnownToBeAPowerOfTwo(Remainder, /*OrZero*/ true) &&
IC.isKnownToBeAPowerOfTwo(Remainder, /*OrZero=*/true) &&
FalseVal == RemRes)
return FoldToBitwiseAnd(Remainder);

Expand Down
15 changes: 15 additions & 0 deletions llvm/test/Transforms/InstCombine/select-divrem.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -322,6 +322,21 @@ define i8 @rem_euclid_non_const_pow2(i8 %0, i8 %1) {
ret i8 %sel
}

define i8 @rem_euclid_non_const_pow2_commuted(i8 %0, i8 %1) {
; CHECK-LABEL: @rem_euclid_non_const_pow2_commuted(
; CHECK-NEXT: [[NOTMASK:%.*]] = shl nsw i8 -1, [[TMP0:%.*]]
; CHECK-NEXT: [[TMP3:%.*]] = xor i8 [[NOTMASK]], -1
; CHECK-NEXT: [[SEL:%.*]] = and i8 [[TMP1:%.*]], [[TMP3]]
; CHECK-NEXT: ret i8 [[SEL]]
;
%pow2 = shl i8 1, %0
%rem = srem i8 %1, %pow2
%cond = icmp slt i8 %rem, 0
%add = add i8 %pow2, %rem
%sel = select i1 %cond, i8 %add, i8 %rem
ret i8 %sel
}

define i32 @rem_euclid_pow2_true_arm_folded(i32 %n) {
; CHECK-LABEL: @rem_euclid_pow2_true_arm_folded(
; CHECK-NEXT: [[RES:%.*]] = and i32 [[N:%.*]], 1
Expand Down
Loading