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95a741163f
Reassociate mutated existing instructions in order to form negations which would create additional reassociate opportunities. This fixes PR23926. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240593 91177308-0d34-0410-b5e6-96231b3b80d8
46 lines
1.1 KiB
LLVM
46 lines
1.1 KiB
LLVM
; RUN: opt < %s -reassociate -dce -S | FileCheck %s
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; PR12985
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; Verify the nsw flags are preserved when converting shl to mul.
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; CHECK-LABEL: @shl_to_mul_nsw(
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; CHECK: %mul = mul i32 %i, -2147483648
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; CHECK: add i32 %mul, 1
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define i32 @shl_to_mul_nsw(i32 %i) {
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entry:
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%mul = shl nsw i32 %i, 31
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%mul2 = add i32 %mul, 1
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ret i32 %mul2
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}
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; CHECK-LABEL: @shl_to_mul_nuw(
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; CHECK: %mul = mul nuw i32 %i, 4
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; CHECK: add i32 %mul, 1
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define i32 @shl_to_mul_nuw(i32 %i) {
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entry:
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%mul = shl nuw i32 %i, 2
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%mul2 = add i32 %mul, 1
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ret i32 %mul2
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}
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; CHECK-LABEL: @shl_to_mul_nuw_nsw(
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; CHECK: %mul = mul nuw nsw i32 %i, 4
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; CHECK: add i32 %mul, 1
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define i32 @shl_to_mul_nuw_nsw(i32 %i) {
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entry:
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%mul = shl nuw nsw i32 %i, 2
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%mul2 = add i32 %mul, 1
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ret i32 %mul2
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}
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; CHECK-LABEL: @pr23926(
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; CHECK: %[[X1_neg:.*]] = sub i2 0, %X1
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; CHECK-NEXT: %[[sub_one:.*]] = add i2 %[[X1_neg]], -1
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; CHECK-NEXT: %[[add:.*]] = add i2 %[[sub_one]], %X2
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; CHECK-NEXT: ret i2 %[[add]]
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define i2 @pr23926(i2 %X1, i2 %X2) {
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%add = add nuw i2 %X1, 1
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%sub = sub nuw nsw i2 %X2, %add
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ret i2 %sub
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}
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