From cc7052343e5e955d4e2f48885c06360f9003390a Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Fri, 15 Nov 2013 19:09:27 +0000 Subject: Avoid illegal integer promotion in fastisel Stop folding constant adds into GEP when the type size doesn't match. Otherwise, the adds' operands are effectively being promoted, changing the conditions of an overflow. Results are different when: sext(a) + sext(b) != sext(a + b) Problem originally found on x86-64, but also fixed issues with ARM and PPC, which used similar code. Patch by Duncan Exon Smith! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194840 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/FastISel.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include') diff --git a/include/llvm/CodeGen/FastISel.h b/include/llvm/CodeGen/FastISel.h index 0063474..1e0ef6b 100644 --- a/include/llvm/CodeGen/FastISel.h +++ b/include/llvm/CodeGen/FastISel.h @@ -358,6 +358,15 @@ protected: return 0; } + /// \brief Check if \c Add is an add that can be safely folded into \c GEP. + /// + /// \c Add can be folded into \c GEP if: + /// - \c Add is an add, + /// - \c Add's size matches \c GEP's, + /// - \c Add is in the same basic block as \c GEP, and + /// - \c Add has a constant operand. + bool canFoldAddIntoGEP(const User *GEP, const Value *Add); + private: bool SelectBinaryOp(const User *I, unsigned ISDOpcode); -- cgit v1.1