37 lines
1 KiB
LLVM
37 lines
1 KiB
LLVM
|
; RUN: opt < %s -aa-pipeline=basic-aa -passes=gvn,instcombine -S | FileCheck %s
|
||
|
|
||
|
declare ptr @test(ptr nocapture)
|
||
|
|
||
|
define i32 @test2() {
|
||
|
; CHECK: ret i32 0
|
||
|
%P = alloca i32
|
||
|
%Q = call ptr @test(ptr %P)
|
||
|
%a = load i32, ptr %P
|
||
|
store i32 4, ptr %Q ;; cannot clobber P since it is nocapture.
|
||
|
%b = load i32, ptr %P
|
||
|
%c = sub i32 %a, %b
|
||
|
ret i32 %c
|
||
|
}
|
||
|
|
||
|
declare void @test3(ptr %p, ptr %q) nounwind
|
||
|
|
||
|
define i32 @test4(ptr noalias nocapture %p) nounwind {
|
||
|
; CHECK: call void @test3
|
||
|
; CHECK: store i32 0, ptr %p
|
||
|
; CHECK: store i32 1, ptr %x
|
||
|
; CHECK: %y = load i32, ptr %p
|
||
|
; CHECK: ret i32 %y
|
||
|
entry:
|
||
|
%q = alloca ptr
|
||
|
; 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(ptr %q, ptr %p) nounwind
|
||
|
store i32 0, ptr %p
|
||
|
%x = load ptr, ptr %q
|
||
|
; This store might write to %p and so we can't eliminate the subsequent
|
||
|
; load
|
||
|
store i32 1, ptr %x
|
||
|
%y = load i32, ptr %p
|
||
|
ret i32 %y
|
||
|
}
|