| ; RUN: opt < %s -basic-aa -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, i32* %P |
| store i32 4, i32* %Q ;; cannot clobber P since it is nocapture. |
| %b = load i32, 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, 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*, 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, i32* %p |
| ret i32 %y |
| } |