| Message ID | 53DF7B10.6080101@arm.com |
|---|---|
| State | New |
| Headers | show |
On 04/08/14 13:22, Kyrill Tkachov wrote: > Hi all, > > While working on another patch and looking at the rbit and clz patterns, > I noticed that in aarch32 the relevant patterns are not adjusted for > -mrestrict-it. > A program like: > int > foo (int a, int b) > { > if (a + 5 == b) > return __builtin_ctz (a); > > return 1; > } > > compiled with -march=armv8-a -mthumb could generate clz and rbit > instructions inside an IT block, thus earning an assembler warning. > Whilst there I also noticed that the output templates for the arm_rev > pattern have a %? that is used to print out condition codes during > predication but the pattern is not marked as predicable. > So I set the predicable attribute there and adjusted it for > -mrestrict-it while at it. > > Ok for trunk? > > 2014-08-04 Kyrylo Tkachov <kyrylo.tkachov@arm.com> > > * config/arm/arm.md (clzsi2): Set predicable_short_it attr to no. > (rbitsi2): Likewise. > (*arm_rev): Set predicable and predicable_short_it attributes. > OK. R.
commit 1ea85f18ff46fa985ba79e6e64715ecf855751c3
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date: Wed Jul 9 16:38:45 2014 +0100
[ARM] Handle IT deprecation for clz, rbit, rev
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 916d552..3e1a1bb 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -10662,6 +10662,7 @@
"TARGET_32BIT && arm_arch5"
"clz%?\\t%0, %1"
[(set_attr "predicable" "yes")
+ (set_attr "predicable_short_it" "no")
(set_attr "type" "clz")])
(define_insn "rbitsi2"
@@ -10670,6 +10671,7 @@
"TARGET_32BIT && arm_arch_thumb2"
"rbit%?\\t%0, %1"
[(set_attr "predicable" "yes")
+ (set_attr "predicable_short_it" "no")
(set_attr "type" "clz")])
(define_expand "ctzsi2"
@@ -10829,6 +10831,8 @@
rev%?\t%0, %1"
[(set_attr "arch" "t1,t2,32")
(set_attr "length" "2,2,4")
+ (set_attr "predicable" "no,yes,yes")
+ (set_attr "predicable_short_it" "no")
(set_attr "type" "rev")]
)
Hi all, While working on another patch and looking at the rbit and clz patterns, I noticed that in aarch32 the relevant patterns are not adjusted for -mrestrict-it. A program like: int foo (int a, int b) { if (a + 5 == b) return __builtin_ctz (a); return 1; } compiled with -march=armv8-a -mthumb could generate clz and rbit instructions inside an IT block, thus earning an assembler warning. Whilst there I also noticed that the output templates for the arm_rev pattern have a %? that is used to print out condition codes during predication but the pattern is not marked as predicable. So I set the predicable attribute there and adjusted it for -mrestrict-it while at it. Ok for trunk? 2014-08-04 Kyrylo Tkachov <kyrylo.tkachov@arm.com> * config/arm/arm.md (clzsi2): Set predicable_short_it attr to no. (rbitsi2): Likewise. (*arm_rev): Set predicable and predicable_short_it attributes.