http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48596
--- Comment #5 from Kazumoto Kojima <kkojima at gcc dot gnu.org> 2011-08-02
23:53:30 UTC ---
I was trying to find a way that solves it without penalizing -O2
or the higher cases, though it's not easy to me. It seems that
the target's register_move_cost is the way to discourage trying
to use FP registers for a pointer. Unfortunately, Pmode is simply
SImode for our case and it also discourages using a FP reg as
a cheap storage for SImode. I've tried
--- ORIG/trunk/gcc/config/sh/sh.c 2011-08-01 09:22:27.000000000 +0900
+++ trunk/gcc/config/sh/sh.c 2011-08-01 09:41:25.000000000 +0900
@@ -11472,8 +11472,18 @@ sh_register_move_cost (enum machine_mode
&& REGCLASS_HAS_GENERAL_REG (srcclass))
|| (REGCLASS_HAS_GENERAL_REG (dstclass)
&& REGCLASS_HAS_FP_REG (srcclass)))
- return ((TARGET_SHMEDIA ? 4 : TARGET_FMOVD ? 8 : 12)
- * ((GET_MODE_SIZE (mode) + 7) / 8U));
+ {
+ if (TARGET_SHMEDIA)
+ return 4 * ((GET_MODE_SIZE (mode) + 7) / 8U);
+ else
+ {
+ /* Discourage trying to use fp regs for a pointer. */
+ int addend = (mode == Pmode) ? 40 : 0;
+
+ return (((TARGET_FMOVD ? 8 : 12) + addend)
+ * ((GET_MODE_SIZE (mode) + 7) / 8U));
+ }
+ }
if ((dstclass == FPUL_REGS
&& REGCLASS_HAS_GENERAL_REG (srcclass))
on the current trunk and observed some CSiBE testresults. A bit
surprisingly, there are no code size regressions and one 2%
improvement for teem-1.6.0-src src/bane/gkmsTxf which reduces
to 3192 bytes from 3256 bytes. Now I'm inclined to apply it
on trunk if it passes the bootstrap/regression/other tests.
