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Re: [Bug tree-optimization/31136] [4.2 Regression] FRE ignores bit-field truncation (C and C++ front-end don't produce bit-field truncation
- From: "Andrew Pinski" <pinskia at gmail dot com>
- To: gcc-bugzilla at gcc dot gnu dot org
- Cc: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 23 Mar 2007 00:57:16 -0700
- Subject: Re: [Bug tree-optimization/31136] [4.2 Regression] FRE ignores bit-field truncation (C and C++ front-end don't produce bit-field truncation
- References: <bug-31136-12896@http.gcc.gnu.org/bugzilla/> <20070323050100.27943.qmail@sourceware.org>
On 23 Mar 2007 05:01:00 -0000, spark at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
The problematic STRIP_SIGN_NOPS() call is from fold_unary()
which is called from try_combine_conversion() in tree-ssa-pre.c.
STRIP_SIGN_NOPS() is called with the expression:
No, STRIP_SIGN_NOPS is correct, just fold_unary is incorrect in its
folding. It should have called fold_convert on the expression if the
types are different and it is a constant.
-- Pinski