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Properly check if a CMPZ node is in fact comparing against zero
This was left implicit and never ever checked, which means we could have a CMPZ against some non-zero value and we were carrying on with BFI conversion regardless. Caught by Oliver Stannard using csmith; regression test added. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253195 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -10398,6 +10398,12 @@ SDValue ARMTargetLowering::PerformCMOVToBFICombine(SDNode *CMOV, SelectionDAG &D
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auto CC = CCNode->getAPIntValue().getLimitedValue();
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SDValue CmpZ = CMOV->getOperand(4);
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// The compare must be against zero.
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SDValue Zero = CmpZ->getOperand(1);
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if (!isa<ConstantSDNode>(Zero.getNode()) ||
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!cast<ConstantSDNode>(Zero.getNode())->isNullValue())
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return SDValue();
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assert(CmpZ->getOpcode() == ARMISD::CMPZ);
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SDValue And = CmpZ->getOperand(0);
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if (And->getOpcode() != ISD::AND)
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@ -158,3 +158,14 @@ define i32 @f12(i32 %x, i32 %y) {
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%sel = select i1 %cmp, i32 %y2, i32 %or
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ret i32 %sel
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}
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define i32 @f13(i32 %x, i32 %y) {
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; CHECK-LABEL: f13:
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; CHECK-NOT: bfi
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%y2 = and i32 %y, 4294967040 ; 0xFFFFFF00
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%and = and i32 %x, 4
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%or = or i32 %y2, 16
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%cmp = icmp eq i32 %and, 42 ; Not comparing against zero!
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%sel = select i1 %cmp, i32 %y2, i32 %or
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ret i32 %sel
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}
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