Hello,
There is another opportunity where SH's addc insn can be used.
Tested on rev 191342 with
make -k check RUNTESTFLAGS="--target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a/-mb,-m4/-ml,-m4/-mb,-m4a/-ml,-m4a/-mb}"
and no new failures.
OK to install?
Cheers,
Oleg
gcc/ChangeLog:
PR target/54236
* config/sh/sh.md (*addc): Add pattern to handle one bit left
shifts.
testsuite/ChangeLog:
PR target/54236
* gcc.target/sh/pr54236-1.c (test_08): Add one bit left shift
case.
Index: gcc/testsuite/gcc.target/sh/pr54236-1.c
===================================================================
--- gcc/testsuite/gcc.target/sh/pr54236-1.c (revision 191342)
+++ gcc/testsuite/gcc.target/sh/pr54236-1.c (working copy)
@@ -4,9 +4,9 @@
/* { dg-do compile { target "sh*-*-*" } } */
/* { dg-options "-O1" } */
/* { dg-skip-if "" { "sh*-*-*" } { "-m5*"} { "" } } */
-/* { dg-final { scan-assembler-times "addc" 3 } } */
+/* { dg-final { scan-assembler-times "addc" 4 } } */
/* { dg-final { scan-assembler-times "subc" 3 } } */
-/* { dg-final { scan-assembler-times "sett" 4 } } */
+/* { dg-final { scan-assembler-times "sett" 5 } } */
/* { dg-final { scan-assembler-times "negc" 1 } } */
/* { dg-final { scan-assembler-not "movt" } } */
@@ -74,3 +74,10 @@
return vi;
}
+
+int
+test_08 (int a)
+{
+ /* 1x addc, 1x sett */
+ return (a << 1) + 1;
+}
Index: gcc/config/sh/sh.md
===================================================================
--- gcc/config/sh/sh.md (revision 191342)
+++ gcc/config/sh/sh.md (working copy)
@@ -1787,6 +1787,22 @@
(reg:SI T_REG)))
(clobber (reg:SI T_REG))])])
+;; Left shifts by one are usually done with an add insn to avoid T_REG
+;; clobbers. Thus addc can also be used to do something like '(x << 1) + 1'.
+(define_insn_and_split "*addc"
+ [(set (match_operand:SI 0 "arith_reg_dest")
+ (plus:SI (mult:SI (match_operand:SI 1 "arith_reg_operand")
+ (const_int 2))
+ (const_int 1)))
+ (clobber (reg:SI T_REG))]
+ "TARGET_SH1"
+ "#"
+ "&& 1"
+ [(set (reg:SI T_REG) (const_int 1))
+ (parallel [(set (match_dup 0) (plus:SI (plus:SI (match_dup 1) (match_dup 1))
+ (reg:SI T_REG)))
+ (clobber (reg:SI T_REG))])])
+
;; Sometimes combine will try to do 'reg + (0-reg) + 1' if the *addc pattern
;; matched. Split this up into a simple sub add sequence, as this will save
;; us one sett insn.
