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Re: [PATCH, ARM] stop changing signedness in PROMOTE_MODE
- From: Jim Wilson <jim dot wilson at linaro dot org>
- To: Jeff Law <law at redhat dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 10 Jul 2015 08:34:57 -0700
- Subject: Re: [PATCH, ARM] stop changing signedness in PROMOTE_MODE
- Authentication-results: sourceware.org; auth=none
- References: <CABXYE2VXjy7=5Y=c1TCxLE8KuwLtwBYBhTB24xrWDvWAeiBwbQ at mail dot gmail dot com> <559BEB2D dot 7040800 at redhat dot com> <CABXYE2UbBP24fBEgDJp5+S1fhFpNHPJgjM=SypsWbc4hV1xbbw at mail dot gmail dot com> <559DAA34 dot 10707 at redhat dot com>
On Wed, Jul 8, 2015 at 3:54 PM, Jeff Law <law@redhat.com> wrote:
> On 07/07/2015 10:29 AM, Jim Wilson wrote:
> This is critically important as various parts of the compiler will take a
> degenerate PHI node and propagate the RHS of the PHI into the uses of the
> LHS of the PHI -- without doing any conversions.
I think this is OK, because tree-outof-ssa does send code in basic
blocks through expand_expr, which will emit conversions if necessary.
it is only the conversion of PHI nodes to RTL that is the problem, as
it doesn't use expand_expr, and hence doesn't get the
SUBREG_PROMOTED_P conversions.
Jim