llvm-project/llvm/test/Transforms/InstCombine/pr31990_wrong_memcpy.ll

26 lines
687 B
LLVM

; RUN: opt -S -instcombine %s -o - | FileCheck %s
; Regression test of PR31990. A memcpy of one byte, copying 0xff, was
; replaced with a single store of an i4 0xf.
@g = constant i8 -1
define void @foo() {
entry:
%0 = alloca i8
%1 = bitcast i8* %0 to i4*
call void @bar(i4* %1)
%2 = bitcast i4* %1 to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %2, i8* @g, i32 1, i1 false)
call void @gaz(i8* %2)
ret void
}
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture writeonly, i8* nocapture readonly, i32, i1)
declare void @bar(i4*)
declare void @gaz(i8*)
; The mempcy should be simplified to a single store of an i8, not i4
; CHECK: store i8 -1
; CHECK-NOT: store i4 -1