Hello!
Attached patch enables flag_ree at -O2 and higher on alpha. Alpha has
certain instructions with implicit SI->DI sign extension, and new REE
pass can merge explicit sign conversions to them without problems.
For example, compiling combine.c with (+) and without (-) REE pass
results in following changes:
cmpeq $10,$9,$2 # 108 *setcc_internal [length = 4]
bne $2,$L76 # 109 *bcc_normal [length = 4]
ldl $2,0($9) # 121 *extendsidi2_1/2 [length = 4]
- zapnot $2,3,$2 # 123 zero_extendhisi2/1 [length = 4]
- addl $31,$2,$2 # 124 *extendsidi2_1/1 [length = 4]
+ zapnot $2,3,$2 # 123 zero_extendhidi2/1 [length = 4]
s4addq $2,$11,$2 # 126 *saddq/1 [length = 4]
ldl $2,0($2) # 127 *extendsidi2_1/2 [length = 4]
zapnot $2,15,$2 # 128 zero_extendsidi2 [length = 4]
and
zapnot $1,15,$4 # 114 zero_extendsidi2 [length = 4]
- addl $1,1,$1 # 119 addsi3/1 [length = 4]
+ addl $1,1,$1 # 119 *addsi_se/1 [length = 4]
sll $4,6,$4 # 115 ashldi3/2 [length = 4]
zapnot $1,15,$2 # 122 zero_extendsidi2 [length = 4]
addq $6,$4,$4 # 116 *adddi_internal/1 [length = 4]
cmpeq $2,$3,$2 # 124 *setcc_internal [length = 4]
- cpys $f31,$f31,$f31 # 446 fnop [length = 4]
stl $5,32($4) # 118 *movsi/6 [length = 4]
- addl $31,$1,$1 # 120 *extendsidi2_1/1 [length = 4]
beq $2,$L85 # 125 *bcc_normal [length = 4]
br $31,$L80 # 438 jump [length = 4]
There are quite some occurrences, showing that redundant extensions
removal pass is effective on alpha.
2011-12-22 Uros Bizjak <ubiz...@gmail.com>
PR target/27468
* config/alpha/alpha.c (alpha_option_override): Enable flag_ree
at -O2 or higher.
Patch was bootstrapped and regression tested on alphaev68-pc-linux-gnu.
OK for mainline?
Uros.
Index: alpha.c
===================================================================
--- alpha.c (revision 182615)
+++ alpha.c (working copy)
@@ -412,6 +412,10 @@ alpha_option_override (void)
alpha_memory_latency = lat;
}
+ /* Enable redundant extension instructions removal at -O2 and higher. */
+ if (optimize >= 2 && !global_options_set.x_flag_ree)
+ flag_ree = 1;
+
/* Default the definition of "small data" to 8 bytes. */
if (!global_options_set.x_g_switch_value)
g_switch_value = 8;
