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PATCH: Change pa FP register alloc order
- To: egcs-patches at egcs dot cygnus dot com
- Subject: PATCH: Change pa FP register alloc order
- From: "Jerry Quinn" <jquinn at nortelnetworks dot com>
- Date: Fri, 26 Feb 1999 13:12:30 -0500
- Organization: Nortel Technology
OK, here is the simple patch to rearrange the register allocation order
for PA platforms. I haven't seen any performance problems on 1.1
processors so the change is directly to REG_ALLOC_ORDER. If you still
want, I'll go back and make it switchable.
Here is the changelog entry:
Fri Feb 26 13:05:09 EST 1999 Jerry Quinn <jquinn@nortelnetworks.com>
* config/pa/pa.h (REG_ALLOC_ORDER): Change order to allocate float L
regs before R regs
--- origsrc/gcc/config/pa/pa.h Thu Feb 25 09:59:30 1999
+++ src/gcc/config/pa/pa.h Thu Feb 25 10:08:33 1999
@@ -563,23 +563,29 @@
registers will generally not be allocated across a call).
Experimentation has shown slightly better results by allocating
- FP registers first. */
+ FP registers first.
+
+ FP registers are ordered so that all L registers are selected before
+ R registers. This works around a single-precision problem on PA8000
+ where the L and R halves of a register are interlocked. */
#define REG_ALLOC_ORDER \
{ \
/* caller-saved fp regs. */ \
- 68, 69, 70, 71, 72, 73, 74, 75, \
- 76, 77, 78, 79, 80, 81, 82, 83, \
- 84, 85, 86, 87, \
- 40, 41, 42, 43, 44, 45, 46, 47, \
- 32, 33, 34, 35, 36, 37, 38, 39, \
+ 68, 70, 72, 74, 76, 78, 80, 82, \
+ 84, 86, 40, 42, 44, 46, 32, 34, \
+ 36, 38, \
+ 69, 71, 73, 75, 77, 79, 81, 83, \
+ 85, 87, 41, 43, 45, 47, 33, 35, \
+ 37, 39, \
/* caller-saved general regs. */ \
19, 20, 21, 22, 23, 24, 25, 26, \
27, 28, 29, 31, 2, \
/* callee-saved fp regs. */ \
- 48, 49, 50, 51, 52, 53, 54, 55, \
- 56, 57, 58, 59, 60, 61, 62, 63, \
- 64, 65, 66, 67, \
+ 48, 50, 52, 54, 56, 58, 60, 62, \
+ 64, 66, \
+ 49, 51, 53, 55, 57, 59, 61, 63, \
+ 65, 67, \
/* callee-saved general regs. */ \
3, 4, 5, 6, 7, 8, 9, 10, \
11, 12, 13, 14, 15, 16, 17, 18, \
--
Jerry Quinn Tel: (514) 761-8737
jquinn@nortelnetworks.com Fax: (514) 761-8505
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