From 2715a581494ef0c7f7403f9f7dbe4c0d052d61a5 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Fri, 11 Mar 2011 14:46:49 +0000 Subject: ComputeMaskedBits: sub falls through to add, and sub doesn't have the same overflow semantics as add. Should fix the selfhost failures that started with r127463. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127465 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'lib/Analysis/ValueTracking.cpp') diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 33fb1e8..6c33d2d 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -431,7 +431,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, } // Are we still trying to solve for the sign bit? - if (Mask.isNegative() && !KnownZero.isNegative() && !KnownOne.isNegative()){ + if (I->getOpcode() == Instruction::Add && + Mask.isNegative() && !KnownZero.isNegative() && !KnownOne.isNegative()){ OverflowingBinaryOperator *OBO = cast(I); if (OBO->hasNoSignedWrap()) { // Adding two positive numbers can't wrap into negative ... -- cgit v1.1