2dd52b4527
Instead of relying on constant operands, use known bits to do the computation. Proofs: https://alive2.llvm.org/ce/z/M-aBnw Differential Revision: https://reviews.llvm.org/D157532
21 lines
698 B
LLVM
21 lines
698 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=instcombine -S | FileCheck %s
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; PR49778: this should not be folded to 0.
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define i32 @src(i1 %x2) {
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; CHECK-LABEL: @src(
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; CHECK-NEXT: [[X13:%.*]] = zext i1 [[X2:%.*]] to i32
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; CHECK-NEXT: [[_7:%.*]] = shl nsw i32 -1, [[X13]]
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; CHECK-NEXT: [[MASK:%.*]] = xor i32 [[_7]], -1
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; CHECK-NEXT: [[_8:%.*]] = and i32 [[MASK]], [[X13]]
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; CHECK-NEXT: [[_9:%.*]] = shl nuw nsw i32 [[_8]], [[X13]]
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; CHECK-NEXT: ret i32 [[_9]]
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;
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%x13 = zext i1 %x2 to i32
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%_7 = shl i32 4294967295, %x13
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%mask = xor i32 %_7, 4294967295
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%_8 = and i32 %mask, %x13
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%_9 = shl i32 %_8, %x13
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ret i32 %_9
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}
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