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98726c311b
Fixes exponential compilation complexity in PR19835, caused by LICM::sink not handling the following pattern well: f = op g e = op f, g d = op e c = op d, e b = op c a = op b, c When an instruction with N uses is sunk, each of its operands gets N new uses (all of them - phi nodes). In the example above, if a had 1 use, c would have 2, e would have 4, and g would have 8. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211673 91177308-0d34-0410-b5e6-96231b3b80d8
30 lines
939 B
LLVM
30 lines
939 B
LLVM
; RUN: opt < %s -licm -S | FileCheck %s
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; PR19835
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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define i32 @f(i32 %x) {
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entry:
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br label %for.body
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for.body: ; preds = %entry, %for.body
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%storemerge4 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
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%mul = mul nsw i32 %x, %x
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%add2 = add nsw i32 %mul, %x
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%mul3 = add nsw i32 %add2, %mul
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%inc = add nsw i32 %storemerge4, 1
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%cmp = icmp slt i32 %inc, 100
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br i1 %cmp, label %for.body, label %for.end
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for.end: ; preds = %for.body
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%a9.0.lcssa = phi i32 [ %mul3, %for.body ]
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ret i32 %a9.0.lcssa
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}
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; Test that there is exactly one copy of mul nsw i32 %x, %x in the exit block.
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; CHECK: define i32 @f(i32 [[X:%.*]])
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; CHECK: for.end:
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; CHECK-NOT: mul nsw i32 [[X]], [[X]]
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; CHECK: mul nsw i32 [[X]], [[X]]
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; CHECK-NOT: mul nsw i32 [[X]], [[X]]
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