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llvm-mirror/test/CodeGen/AArch64/tail-call-unused-zext.ll
Francis Visoiu Mistrih 3a33d73f69 [CodeGen] Ignore return sext/zext attributes of unused results for tail calls
If the caller's return type does not have a zeroext attribute but the
callee does a tail call zeroext, we won't consider the tail call during
CodeGenPrepare because the attributes don't match.

However, if the result of the tail call has no uses, it makes sense to
drop the sext/zext attributes.

Differential Revision: https://reviews.llvm.org/D56486

llvm-svn: 350753
2019-01-09 19:46:15 +00:00

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1.0 KiB
LLVM

; RUN: llc -mtriple=arm64--- -stop-after=expand-isel-pseudos -o - %s | FileCheck %s
; Check that we ignore the zeroext attribute on the return type of the tail
; call, since the return value is unused. This happens during CodeGenPrepare in
; dupRetToEnableTailCallOpts, which calls attributesPermitTailCall to check if
; the attributes of the caller and the callee match.
declare zeroext i1 @zcallee()
define void @zcaller() {
; CHECK-LABEL: name: zcaller
entry:
br i1 undef, label %calllabel, label %retlabel
calllabel:
; CHECK: bb.1.calllabel:
; CHECK-NOT: BL @zcallee
; CHECK-NEXT: TCRETURNdi @zcallee
%unused_result = tail call zeroext i1 @zcallee()
br label %retlabel
retlabel:
ret void
}
declare signext i1 @scallee()
define void @scaller() {
; CHECK-LABEL: name: scaller
entry:
br i1 undef, label %calllabel, label %retlabel
calllabel:
; CHECK: bb.1.calllabel:
; CHECK-NOT: BL @scallee
; CHECK-NEXT: TCRETURNdi @scallee
%unused_result = tail call signext i1 @scallee()
br label %retlabel
retlabel:
ret void
}