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6c2e8874b0
InstCombineMulDivRem has: // Canonicalize (X+C1)*CI -> X*CI+C1*CI. InstCombineAddSub has: // W*X + Y*Z --> W * (X+Z) iff W == Y These two transforms could fight with each other if C1*CI would not fold away to something simpler than a ConstantExpr mul. The InstCombineMulDivRem transform only acted on ConstantInts until r199602 when it was changed to operate on all Constants in order to let it fire on ConstantVectors. To fix this, make this transform more careful by checking to see if we actually folded away C1*CI. This fixes PR20079. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211258 91177308-0d34-0410-b5e6-96231b3b80d8
14 lines
572 B
LLVM
14 lines
572 B
LLVM
; RUN: opt -S -instcombine < %s | FileCheck %s
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@b = internal global [1 x i32] zeroinitializer, align 4
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@c = internal global i32 0, align 4
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; CHECK-LABEL: @fn1
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; CHECK: [[ADD:%.*]] = add i32 %a, -1
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; CHECK-NEXT: [[AND:%.*]] = and i32 [[ADD]], sub (i32 0, i32 zext (i1 icmp eq (i32* getelementptr inbounds ([1 x i32]* @b, i64 0, i64 0), i32* @c) to i32))
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; CHECK-NEXT: ret i32 [[AND]]
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define i32 @fn1(i32 %a) {
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%xor = add i32 %a, -1
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%mul = mul nsw i32 %xor, zext (i1 icmp eq (i32* getelementptr inbounds ([1 x i32]* @b, i64 0, i64 0), i32* @c) to i32)
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ret i32 %mul
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}
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