Commit c15ccfb2 authored by Nikita Popov's avatar Nikita Popov
Browse files

[InstCombine] Fix select + cast fold with constant expression (PR64669) 

The zext constant expression was detected by the fold, but then
handled as a sext. Use ZExtOperator instead of ZExtInst to handle
constant expressions.

Fixes https://github.com/llvm/llvm-project/issues/64669.
parent f44beecb

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

+1 −1
Original line number Diff line number Diff line
@@ -908,7 +908,7 @@ InstCombinerImpl::foldBinOpOfSelectAndCastOfSelectCondition(BinaryOperator &I) { 


  auto NewFoldedConst = [&](bool IsTrueArm, Value *V) {

    bool IsCastOpRHS = (CastOp == RHS);

    bool IsZExt = isa<ZExtInst>(CastOp);

    bool IsZExt = isa<ZExtOperator>(CastOp);

    Constant *C;



    if (IsTrueArm) {

llvm/test/Transforms/InstCombine/binop-select-cast-of-select-cond.ll

+16 −0
Original line number Diff line number Diff line
@@ -224,3 +224,19 @@ define <2 x i8> @vectorized_add(<2 x i1> %c, <2 x i8> %arg) { 
  %add = add <2 x i8> %sel, %zext

  ret <2 x i8> %add

}



@b = external global [72 x i32]

@c = external global i32



define i64 @pr64669(i64 %a) {

; CHECK-LABEL: define i64 @pr64669

; CHECK-SAME: (i64 [[A:%.*]]) {

; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[A]], 1

; CHECK-NEXT:    [[ADD:%.*]] = select i1 icmp ne (ptr getelementptr inbounds ([72 x i32], ptr @b, i64 0, i64 25), ptr @c), i64 [[TMP1]], i64 0

; CHECK-NEXT:    ret i64 [[ADD]]

;

  %mul = select i1 icmp ne (ptr getelementptr inbounds ([72 x i32], ptr @b, i64 0, i64 25), ptr @c), i64 %a, i64 0

  %conv3 = zext i1 icmp ne (ptr getelementptr inbounds ([72 x i32], ptr @b, i64 0, i64 25), ptr @c) to i64

  %add = add nsw i64 %mul, %conv3

  ret i64 %add

}