| ; Test that GCSE uses basicaa to do alias analysis, which is capable of |
| ; disambiguating some obvious cases. All loads should be removable in |
| ; this testcase. |
| |
| ; RUN: opt < %s -basic-aa -gvn -instcombine -dce -S | FileCheck %s |
| |
| @A = global i32 7 |
| @B = global i32 8 |
| |
| ; CHECK: define i32 @test() |
| ; CHECK-NEXT: store i32 123, i32* @B |
| ; CHECK-NEXT: ret i32 0 |
| |
| define i32 @test() { |
| %A1 = load i32, i32* @A |
| |
| store i32 123, i32* @B ; Store cannot alias @A |
| |
| %A2 = load i32, i32* @A |
| %X = sub i32 %A1, %A2 |
| ret i32 %X |
| } |
| |
| ; CHECK: define i32 @test2() |
| ; CHECK-NEXT: br label %Loop |
| ; CHECK: Loop: |
| ; CHECK-NEXT: store i32 0, i32* @B |
| ; CHECK-NEXT: br i1 true, label %out, label %Loop |
| ; CHECK: out: |
| ; CHECK-NEXT: ret i32 0 |
| |
| define i32 @test2() { |
| %A1 = load i32, i32* @A |
| br label %Loop |
| Loop: |
| %AP = phi i32 [0, %0], [%X, %Loop] |
| store i32 %AP, i32* @B ; Store cannot alias @A |
| |
| %A2 = load i32, i32* @A |
| %X = sub i32 %A1, %A2 |
| %c = icmp eq i32 %X, 0 |
| br i1 %c, label %out, label %Loop |
| |
| out: |
| ret i32 %X |
| } |
| |
| declare void @external() |
| |
| ; CHECK: define i32 @test3() |
| ; CHECK-NEXT: call void @external() |
| ; CHECK-NEXT: ret i32 7 |
| |
| define i32 @test3() { |
| %X = alloca i32 |
| store i32 7, i32* %X |
| call void @external() |
| %V = load i32, i32* %X |
| ret i32 %V |
| } |
| |