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[PATCH 5/5] Remove CANNOT_CHANGE_MODE_CLASS workaround in i386.c
- From: Richard Sandiford <richard dot sandiford at arm dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 18 Sep 2014 11:26:38 +0100
- Subject: [PATCH 5/5] Remove CANNOT_CHANGE_MODE_CLASS workaround in i386.c
- Authentication-results: sourceware.org; auth=none
- References: <87ppetnsxd dot fsf at e105548-lin dot cambridge dot arm dot com>
Patch 4 should make it possible to relax i386'a CANNOT_CHANGE_MODE_CLASS,
solving the missed optimisation that triggered the original thread.
gcc/
* config/i386/i386.c (ix86_cannot_change_mode_class): Remove
GET_MODE_SIZE (to) < GET_MODE_SIZE (from) test.
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c 2014-09-15 09:48:11.310438531 +0100
+++ gcc/config/i386/i386.c 2014-09-15 09:48:11.310438531 +0100
@@ -37526,13 +37526,6 @@ ix86_cannot_change_mode_class (enum mach
the vec_dupv4hi pattern. */
if (GET_MODE_SIZE (from) < 4)
return true;
-
- /* Vector registers do not support subreg with nonzero offsets, which
- are otherwise valid for integer registers. Since we can't see
- whether we have a nonzero offset from here, prohibit all
- nonparadoxical subregs changing size. */
- if (GET_MODE_SIZE (to) < GET_MODE_SIZE (from))
- return true;
}
return false;