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Re: [PATCH, rs6000] Use new __builtin_pack_longdouble within libgcc's ibm-ldouble.c
- From: Mike Stump <mikestump at comcast dot net>
- To: Peter Bergner <bergner at vnet dot ibm dot com>
- Cc: David Edelsohn <dje dot gcc at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Alan Modra <amodra at gmail dot com>
- Date: Tue, 29 Jul 2014 10:11:08 -0700
- Subject: Re: [PATCH, rs6000] Use new __builtin_pack_longdouble within libgcc's ibm-ldouble.c
- Authentication-results: sourceware.org; auth=none
- References: <1406645783 dot 6052 dot 52 dot camel at otta>
On Jul 29, 2014, at 7:56 AM, Peter Bergner <firstname.lastname@example.org> wrote:
> Currently, the IBM long double routines in libgcc use a union to construct
> a long double from two double values. This causes horrific code generation
> that copies the two double from the FP registers over to GPRs and back
> again, giving us two loads and two stores, which leads to two load-hit-store
Gosh, it’s too bad we don’t have any sort of technology to optimize moving data around.