1 ; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -instcombine -S | FileCheck %s 2 ; Checks that the select-icmp optimization is safe in two cases 3 declare void @foo(i32) 4 declare i32 @bar(i32) 5 6 ; don't replace 'cond' by 'len' in the home block ('bb') that 7 ; contains the select 8 define void @test1(i32 %len) { 9 entry: 10 br label %bb 11 12 bb: 13 %cmp = icmp ult i32 %len, 8 14 %cond = select i1 %cmp, i32 %len, i32 8 15 call void @foo(i32 %cond) 16 %cmp11 = icmp eq i32 %cond, 8 17 br i1 %cmp11, label %for.end, label %bb 18 19 for.end: 20 ret void 21 ; CHECK: select 22 ; CHECK: icmp eq i32 %cond, 8 23 } 24 25 ; don't replace 'cond' by 'len' in a block ('b1') that dominates all uses 26 ; of the select outside the home block ('bb'), but can be reached from the home 27 ; block on another path ('bb -> b0 -> b1') 28 define void @test2(i32 %len) { 29 entry: 30 %0 = call i32 @bar(i32 %len); 31 %cmp = icmp ult i32 %len, 4 32 br i1 %cmp, label %bb, label %b1 33 bb: 34 %cmp2 = icmp ult i32 %0, 2 35 %cond = select i1 %cmp2, i32 %len, i32 8 36 %cmp3 = icmp eq i32 %cond, 8 37 br i1 %cmp3, label %b0, label %b1 38 39 b0: 40 call void @foo(i32 %len) 41 br label %b1 42 43 b1: 44 ; CHECK: phi i32 [ %cond, %bb ], [ undef, %b0 ], [ %0, %entry ] 45 %1 = phi i32 [ %cond, %bb ], [ undef, %b0 ], [ %0, %entry ] 46 br label %ret 47 48 ret: 49 call void @foo(i32 %1) 50 ret void 51 } 52
