2833966a3c
Summary: If the branch that leads to the PHI node and the Select instruction depend on correlated conditions, we might be able to directly use the corresponding value from the Select instruction as the incoming value for the PHI node, allowing later removal of the select instruction. Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9051 llvm-svn: 237201
54 lines
924 B
LLVM
54 lines
924 B
LLVM
; RUN: opt < %s -correlated-propagation -S | FileCheck %s
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; CHECK-LABEL: @simple(
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define i8 @simple(i1) {
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entry:
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%s = select i1 %0, i8 0, i8 1
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br i1 %0, label %then, label %else
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then:
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; CHECK: ret i8 0
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%a = phi i8 [ %s, %entry ]
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ret i8 %a
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else:
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; CHECK: ret i8 1
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%b = phi i8 [ %s, %entry ]
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ret i8 %b
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}
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; CHECK-LABEL: @loop(
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define void @loop(i32) {
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entry:
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br label %loop
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loop:
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%idx = phi i32 [ %0, %entry ], [ %sel, %loop ]
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; CHECK: %idx = phi i32 [ %0, %entry ], [ %2, %loop ]
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%1 = icmp eq i32 %idx, 0
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%2 = add i32 %idx, -1
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%sel = select i1 %1, i32 0, i32 %2
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br i1 %1, label %out, label %loop
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out:
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ret void
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}
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; CHECK-LABEL: @not_correlated(
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define i8 @not_correlated(i1, i1) {
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entry:
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%s = select i1 %0, i8 0, i8 1
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br i1 %1, label %then, label %else
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then:
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; CHECK: ret i8 %s
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%a = phi i8 [ %s, %entry ]
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ret i8 %a
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else:
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; CHECK: ret i8 %s
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%b = phi i8 [ %s, %entry ]
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ret i8 %b
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}
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