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23dbc8c364
Summary: This change teaches ScalarEvolution::isLoopBackedgeGuardedByCond to look at edges within the loop body that dominate the latch. We don't do an exhaustive search for all possible edges, but only a quick walk up the dom tree. This re-lands r233447. r233447 was reverted because it caused massive compile-time regressions. This change has a fix for the same issue. llvm-svn: 233829
56 lines
1.4 KiB
LLVM
56 lines
1.4 KiB
LLVM
; RUN: opt -S -indvars < %s | FileCheck %s
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declare void @side_effect(i1)
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define void @latch_dominating_0(i8 %start) {
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; CHECK-LABEL: latch_dominating_0
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entry:
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%e = icmp slt i8 %start, 42
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br i1 %e, label %loop, label %exit
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loop:
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; CHECK-LABEL: loop
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%idx = phi i8 [ %start, %entry ], [ %idx.inc, %be ]
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%idx.inc = add i8 %idx, 1
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%folds.to.true = icmp slt i8 %idx, 42
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; CHECK: call void @side_effect(i1 true)
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call void @side_effect(i1 %folds.to.true)
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%c0 = icmp slt i8 %idx.inc, 42
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br i1 %c0, label %be, label %exit
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be:
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; CHECK: call void @side_effect(i1 true)
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call void @side_effect(i1 %folds.to.true)
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%c1 = icmp slt i8 %idx.inc, 100
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br i1 %c1, label %loop, label %exit
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exit:
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ret void
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}
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define void @latch_dominating_1(i8 %start) {
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; CHECK-LABEL: latch_dominating_1
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entry:
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%e = icmp slt i8 %start, 42
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br i1 %e, label %loop, label %exit
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loop:
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; CHECK-LABEL: loop
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%idx = phi i8 [ %start, %entry ], [ %idx.inc, %be ]
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%idx.inc = add i8 %idx, 1
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%does.not.fold.to.true = icmp slt i8 %idx, 42
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; CHECK: call void @side_effect(i1 %does.not.fold.to.true)
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call void @side_effect(i1 %does.not.fold.to.true)
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%c0 = icmp slt i8 %idx.inc, 42
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br i1 %c0, label %be, label %be
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be:
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; CHECK: call void @side_effect(i1 %does.not.fold.to.true)
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call void @side_effect(i1 %does.not.fold.to.true)
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%c1 = icmp slt i8 %idx.inc, 100
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br i1 %c1, label %loop, label %exit
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exit:
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ret void
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}
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