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i386 CLASS_MAX_NREGS fix and REGISTER_MOVE_COST tweek
- To: patches at x86-64 dot org, rth at cygnus dot com, gcc-patches at gcc dot gnu dot org
- Subject: i386 CLASS_MAX_NREGS fix and REGISTER_MOVE_COST tweek
- From: Jan Hubicka <jh at suse dot cz>
- Date: Sun, 8 Apr 2001 00:52:08 +0200
Hi
The CLASS_MAX_NREGS tends to overestimate the compund SSE/FLOAT classes
and MEMORY_MOVE_COST returns 20 as arbitary high cost, that is lower
than real move cost of PPro.
This patch fixes both resulting in more sane regsiter preferencing.
Sun Apr 8 00:48:59 CEST 2001 Jan Hubicka <jh@suse.cz>
* i386.c (ix86_register_move_cost): Fix handling of reformating penalty
* i386.h (INTEGER_CLASS_P, MAYBE_INTEGER_CLASS_P): New.
(CLASS_MAX_NREGS): Use it.
Index: i386.c
===================================================================
RCS file: /home/cvs/Repository/gcc/gcc/config/i386/i386.c,v
retrieving revision 1.55
diff -c -3 -p -r1.55 i386.c
*** i386.c 2001/04/05 16:20:08 1.55
--- i386.c 2001/04/07 22:45:45
*************** ix86_register_move_cost (mode, class1, c
*** 11633,11645 ****
stall. Count this as arbitarily high cost of 20. */
if (ix86_secondary_memory_needed (class1, class2, mode, 0))
{
if (CLASS_MAX_NREGS (class1, mode) > CLASS_MAX_NREGS (class2, mode))
! return 10;
return (MEMORY_MOVE_COST (mode, class1, 0)
! + MEMORY_MOVE_COST (mode, class2, 1));
}
! /* Moves between SSE/MMX and integer unit are expensive.
! ??? We should make this cost CPU specific. */
if (MMX_CLASS_P (class1) != MMX_CLASS_P (class2)
|| SSE_CLASS_P (class1) != SSE_CLASS_P (class2))
return ix86_cost->mmxsse_to_integer;
--- 11633,11645 ----
stall. Count this as arbitarily high cost of 20. */
if (ix86_secondary_memory_needed (class1, class2, mode, 0))
{
+ int add_cost = 0;
if (CLASS_MAX_NREGS (class1, mode) > CLASS_MAX_NREGS (class2, mode))
! add_cost = 20;
return (MEMORY_MOVE_COST (mode, class1, 0)
! + MEMORY_MOVE_COST (mode, class2, 1) + add_cost);
}
! /* Moves between SSE/MMX and integer unit are expensive. */
if (MMX_CLASS_P (class1) != MMX_CLASS_P (class2)
|| SSE_CLASS_P (class1) != SSE_CLASS_P (class2))
return ix86_cost->mmxsse_to_integer;
Index: i386.h
===================================================================
RCS file: /home/cvs/Repository/gcc/gcc/config/i386/i386.h,v
retrieving revision 1.40
diff -c -3 -p -r1.40 i386.h
*** i386.h 2001/04/04 11:57:08 1.40
--- i386.h 2001/04/07 22:45:46
*************** enum reg_class
*** 1104,1112 ****
--- 1104,1114 ----
#define N_REG_CLASSES (int) LIM_REG_CLASSES
+ #define INTEGER_CLASS_P(CLASS) (reg_class_subset_p (CLASS, GENERAL_REGS))
#define FLOAT_CLASS_P(CLASS) (reg_class_subset_p (CLASS, FLOAT_REGS))
#define SSE_CLASS_P(CLASS) (reg_class_subset_p (CLASS, SSE_REGS))
#define MMX_CLASS_P(CLASS) (reg_class_subset_p (CLASS, MMX_REGS))
+ #define MAYBE_INTEGER_CLASS_P(CLASS) (reg_classes_intersect_p (CLASS, GENERAL_REGS))
#define MAYBE_FLOAT_CLASS_P(CLASS) (reg_classes_intersect_p (CLASS, FLOAT_REGS))
#define MAYBE_SSE_CLASS_P(CLASS) (reg_classes_intersect_p (SSE_REGS, CLASS))
#define MAYBE_MMX_CLASS_P(CLASS) (reg_classes_intersect_p (MMX_REGS, CLASS))
*************** enum reg_class
*** 1353,1361 ****
/* On the 80386, this is the size of MODE in words,
except in the FP regs, where a single reg is always enough. */
#define CLASS_MAX_NREGS(CLASS, MODE) \
! (FLOAT_CLASS_P (CLASS) || SSE_CLASS_P (CLASS) || MMX_CLASS_P (CLASS) \
? 1 \
! : ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
/* A C expression whose value is nonzero if pseudos that have been
assigned to registers of class CLASS would likely be spilled
--- 1355,1364 ----
/* On the 80386, this is the size of MODE in words,
except in the FP regs, where a single reg is always enough. */
#define CLASS_MAX_NREGS(CLASS, MODE) \
! (!MAYBE_INTEGER_CLASS_P (CLASS) \
? 1 \
! : ((GET_MODE_SIZE ((MODE) == TFmode ? XFmode : (MODE)) \
! + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
/* A C expression whose value is nonzero if pseudos that have been
assigned to registers of class CLASS would likely be spilled