| ; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -instcombine -S | FileCheck %s |
| ; Checks that the select-icmp optimization is safe in two cases |
| declare void @foo(i32) |
| declare i32 @bar(i32) |
| |
| ; don't replace 'cond' by 'len' in the home block ('bb') that |
| ; contains the select |
| define void @test1(i32 %len) { |
| entry: |
| br label %bb |
| |
| bb: |
| %cmp = icmp ult i32 %len, 8 |
| %cond = select i1 %cmp, i32 %len, i32 8 |
| call void @foo(i32 %cond) |
| %cmp11 = icmp eq i32 %cond, 8 |
| br i1 %cmp11, label %for.end, label %bb |
| |
| for.end: |
| ret void |
| ; CHECK: select |
| ; CHECK: icmp eq i32 %cond, 8 |
| } |
| |
| ; don't replace 'cond' by 'len' in a block ('b1') that dominates all uses |
| ; of the select outside the home block ('bb'), but can be reached from the home |
| ; block on another path ('bb -> b0 -> b1') |
| define void @test2(i32 %len) { |
| entry: |
| %0 = call i32 @bar(i32 %len); |
| %cmp = icmp ult i32 %len, 4 |
| br i1 %cmp, label %bb, label %b1 |
| bb: |
| %cmp2 = icmp ult i32 %0, 2 |
| %cond = select i1 %cmp2, i32 %len, i32 8 |
| %cmp3 = icmp eq i32 %cond, 8 |
| br i1 %cmp3, label %b0, label %b1 |
| |
| b0: |
| call void @foo(i32 %len) |
| br label %b1 |
| |
| b1: |
| ; CHECK: phi i32 [ %cond, %bb ], [ undef, %b0 ], [ %0, %entry ] |
| %1 = phi i32 [ %cond, %bb ], [ undef, %b0 ], [ %0, %entry ] |
| br label %ret |
| |
| ret: |
| call void @foo(i32 %1) |
| ret void |
| } |