Hello!
Attached patch helps RA to choose the most appropriate PIC register by
changing the register preference for set_got patterns. Using this
patch, there should really be a reason for RA to avoid ABI mandated
hard PIC reg.
This patch avoids many mov %exx,%ebx in front of the calls, that
happen with unpatched compiler even with Vladimir's latest RA patch to
avoid duplicated PIC registers.
As a smoke test, I have checked 32bit libgo.so.6.0.0 library, where now we have:
[uros@omen7 .libs]$ grep thunk.bx aaa | wc -l
7693
[uros@omen7 .libs]$ grep thunk.ax aaa | wc -l
10
[uros@omen7 .libs]$ grep thunk.cx aaa | wc -l
4
[uros@omen7 .libs]$ grep thunk.dx aaa | wc -l
8
[uros@omen7 .libs]$ grep thunk.bp aaa | wc -l
497
[uros@omen7 .libs]$ grep thunk.si aaa | wc -l
145
[uros@omen7 .libs]$ grep thunk.di aaa | wc -l
198
2014-11-27 Uros Bizjak <ubiz...@gmail.com>
* config/i386/i386.md (set_got): Use "=b,?r" constraint for operand 0.
(set_got_labelled): Ditto.
(set_got_rex64): Ditto.
(set_rip_rex64): Ditto.
(set_got_offset_rex64): Ditto.
Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
Thoughts?
Uros
Index: config/i386/i386.md
===================================================================
--- config/i386/i386.md (revision 218111)
+++ config/i386/i386.md (working copy)
@@ -12101,7 +12101,7 @@
"ix86_expand_prologue (); DONE;")
(define_insn "set_got"
- [(set (match_operand:SI 0 "register_operand" "=r")
+ [(set (match_operand:SI 0 "register_operand" "=b,?r")
(unspec:SI [(const_int 0)] UNSPEC_SET_GOT))
(clobber (reg:CC FLAGS_REG))]
"!TARGET_64BIT"
@@ -12110,7 +12110,7 @@
(set_attr "length" "12")])
(define_insn "set_got_labelled"
- [(set (match_operand:SI 0 "register_operand" "=r")
+ [(set (match_operand:SI 0 "register_operand" "=b,?r")
(unspec:SI [(label_ref (match_operand 1))]
UNSPEC_SET_GOT))
(clobber (reg:CC FLAGS_REG))]
@@ -12120,7 +12120,7 @@
(set_attr "length" "12")])
(define_insn "set_got_rex64"
- [(set (match_operand:DI 0 "register_operand" "=r")
+ [(set (match_operand:DI 0 "register_operand" "=b,?r")
(unspec:DI [(const_int 0)] UNSPEC_SET_GOT))]
"TARGET_64BIT"
"lea{q}\t{_GLOBAL_OFFSET_TABLE_(%%rip), %0|%0, _GLOBAL_OFFSET_TABLE_[rip]}"
@@ -12129,7 +12129,7 @@
(set_attr "mode" "DI")])
(define_insn "set_rip_rex64"
- [(set (match_operand:DI 0 "register_operand" "=r")
+ [(set (match_operand:DI 0 "register_operand" "=b,?r")
(unspec:DI [(label_ref (match_operand 1))] UNSPEC_SET_RIP))]
"TARGET_64BIT"
"lea{q}\t{%l1(%%rip), %0|%0, %l1[rip]}"
@@ -12138,7 +12138,7 @@
(set_attr "mode" "DI")])
(define_insn "set_got_offset_rex64"
- [(set (match_operand:DI 0 "register_operand" "=r")
+ [(set (match_operand:DI 0 "register_operand" "=b,?r")
(unspec:DI
[(label_ref (match_operand 1))]
UNSPEC_SET_GOT_OFFSET))]
