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Re: [PATCH] Fix bitfield-- != 0 transformation in fold-const.c
- From: "Paolo Bonzini" <bonzini at gnu dot org>
- To: "Roger Sayle" <roger at eyesopen dot com>
- Cc: <gcc-patches at gcc dot gnu dot org>
- Date: Sat, 6 Mar 2004 15:06:07 +0100
- Subject: Re: [PATCH] Fix bitfield-- != 0 transformation in fold-const.c
! /* This optimization is invalid for ordered comparisons
! if CONST+INCR overflows or if foo+incr might overflow.
! This optimization is invalid for floating point due to rounding.
! For pointer types we assume overflow doesn't happen. */
! && (POINTER_TYPE_P (TREE_TYPE (arg0))
! || (INTEGRAL_TYPE_P (TREE_TYPE (arg0))
! && (code == EQ_EXPR || code == NE_EXPR))))
What about checking for unsignedness or -fwrapv here? Something like
(POINTER_TYPE_P (TREE_TYPE (arg0))
|| (INTEGRAL_TYPE_P (TREE_TYPE (arg0))
&& (code == EQ_EXPR || code == NE_EXPR ||
flag_wrapv || TREE_UNSIGNED (TREE_TYPE (arg0))))
Paolo