This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[Patch,AVR]: Housekeeping: Clean-up notice_update_cc
- From: Georg-Johann Lay <avr at gjlay dot de>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Denis Chertykov <chertykov at gmail dot com>, Anatoly Sokolov <aesok at post dot ru>, Eric Weddington <eric dot weddington at atmel dot com>
- Date: Mon, 26 Sep 2011 17:57:03 +0200
- Subject: [Patch,AVR]: Housekeeping: Clean-up notice_update_cc
This patchlet represents the impact of insn ashrqi3 on CC by means of attribute
"cc" instead of hard-coding it in notice_update_cc.
Testsuite passes fine. Moreover, tested against code like
char c;
void func_1 (char a)
{
a = a >> 7;
if (a)
c = a;
}
that triggered PR39633.
Ok?
Johann
* config/avr/avr.md (ashrqi3): Split alternative "n"
into its remaining parts C03, C04, C05, C06, C07 and describe
impact on CC by attribute "cc" appropriately.
* config/avr/avr.c (notice_update_cc): Clean-up: Don't patch CC0
by digging RTX.
Index: config/avr/avr.md
===================================================================
--- config/avr/avr.md (revision 179191)
+++ config/avr/avr.md (working copy)
@@ -2820,14 +2820,14 @@ (define_insn "*ashlsi3_const"
;; arithmetic shift right
(define_insn "ashrqi3"
- [(set (match_operand:QI 0 "register_operand" "=r,r,r,r,r,r")
- (ashiftrt:QI (match_operand:QI 1 "register_operand" "0,0,0,0,0,0")
- (match_operand:QI 2 "general_operand" "r,L,P,K,n,Qm")))]
+ [(set (match_operand:QI 0 "register_operand" "=r,r,r,r,r ,r ,r")
+ (ashiftrt:QI (match_operand:QI 1 "register_operand" "0,0,0,0,0 ,0 ,0")
+ (match_operand:QI 2 "general_operand" "r,L,P,K,C03 C04 C05,C06 C07,Qm")))]
""
"* return ashrqi3_out (insn, operands, NULL);"
- [(set_attr "length" "5,0,1,2,5,9")
+ [(set_attr "length" "5,0,1,2,5,5,9")
(set_attr "adjust_len" "ashrqi")
- (set_attr "cc" "clobber,none,clobber,clobber,clobber,clobber")])
+ (set_attr "cc" "clobber,none,set_czn,set_czn,set_czn,clobber,clobber")])
(define_insn "ashrhi3"
[(set (match_operand:HI 0 "register_operand" "=r,r,r,r,r,r,r")
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c (revision 179191)
+++ config/avr/avr.c (working copy)
@@ -1574,26 +1574,6 @@ notice_update_cc (rtx body ATTRIBUTE_UNU
case CC_CLOBBER:
/* Insn doesn't leave CC in a usable state. */
CC_STATUS_INIT;
-
- /* Correct CC for the ashrqi3 with the shift count as CONST_INT < 6 */
- set = single_set (insn);
- if (set)
- {
- rtx src = SET_SRC (set);
-
- if (GET_CODE (src) == ASHIFTRT
- && GET_MODE (src) == QImode)
- {
- rtx x = XEXP (src, 1);
-
- if (CONST_INT_P (x)
- && IN_RANGE (INTVAL (x), 1, 5))
- {
- cc_status.value1 = SET_DEST (set);
- cc_status.flags |= CC_OVERFLOW_UNUSABLE;
- }
- }
- }
break;
}
}