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