forked from OSchip/llvm-project
37 lines
1.0 KiB
LLVM
37 lines
1.0 KiB
LLVM
; RUN: opt < %s -basicaa -gvn -instcombine -S | FileCheck %s
|
|
|
|
declare i32* @test(i32* nocapture)
|
|
|
|
define i32 @test2() {
|
|
; CHECK: ret i32 0
|
|
%P = alloca i32
|
|
%Q = call i32* @test(i32* %P)
|
|
%a = load i32* %P
|
|
store i32 4, i32* %Q ;; cannot clobber P since it is nocapture.
|
|
%b = load i32* %P
|
|
%c = sub i32 %a, %b
|
|
ret i32 %c
|
|
}
|
|
|
|
declare void @test3(i32** %p, i32* %q) nounwind
|
|
|
|
define i32 @test4(i32* noalias nocapture %p) nounwind {
|
|
; CHECK: call void @test3
|
|
; CHECK: store i32 0, i32* %p
|
|
; CHECK: store i32 1, i32* %x
|
|
; CHECK: %y = load i32* %p
|
|
; CHECK: ret i32 %y
|
|
entry:
|
|
%q = alloca i32*
|
|
; Here test3 might store %p to %q. This doesn't violate %p's nocapture
|
|
; attribute since the copy doesn't outlive the function.
|
|
call void @test3(i32** %q, i32* %p) nounwind
|
|
store i32 0, i32* %p
|
|
%x = load i32** %q
|
|
; This store might write to %p and so we can't eliminate the subsequent
|
|
; load
|
|
store i32 1, i32* %x
|
|
%y = load i32* %p
|
|
ret i32 %y
|
|
}
|