llvm-6502/test/Transforms/InstCombine/pr21210.ll
Gerolf Hoflehner 5182ad54b2 [InstCombine] Re-commit of r218721 (Optimize icmp-select-icmp sequence)
Fixes the self-host fail. Note that this commit activates dominator
analysis in the combiner by default (like the original commit did).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222590 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-21 23:36:44 +00:00

51 lines
1.2 KiB
LLVM

; 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:
%cond = select i1 %cmp, i32 %len, i32 8
%cmp11 = icmp eq i32 %cond, 8
br i1 %cmp11, 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
}