Hello,
This adds two new patterns to undo an optimization that is done by ifcvt
and is not beneficial if zero displacement branches are available on SH.
Tested on rev 190459 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?
Cheers,
Oleg
ChangeLog:
PR target/51244
* config/sh/sh.md (*cset_zero): New insns.
testsuite/ChangeLog:
PR target/51244
* gcc.target/sh/pr51244-11.c: New.
Index: gcc/config/sh/sh.md
===
--- gcc/config/sh/sh.md (revision 190459)
+++ gcc/config/sh/sh.md (working copy)
@@ -10409,6 +10409,41 @@
operands[0] = gen_reg_rtx (SImode);
})
+;; The *cset_zero patterns convert optimizations such as
+;; if (test) x = 0; to x = -(test == 0);
+;; back to conditional branch sequences if zero-displacement branches
+;; are enabled.
+;; FIXME: These patterns can be removed when conditional execution patterns
+;; are implemented, since ifcvt will not perform these optimizations if
+;; conditional execution is supported.
+(define_insn *cset_zero
+ [(set (match_operand:SI 0 arith_reg_dest =r)
+ (and:SI (plus:SI (match_operand:SI 1 t_reg_operand)
+ (const_int -1))
+ (match_operand:SI 2 arith_reg_operand 0)))]
+ TARGET_SH1 TARGET_ZDCBRANCH
+{
+ return bf 0f \n
+ mov #0,%0 \n
+ 0:;
+}
+ [(set_attr type arith) ;; poor approximation
+ (set_attr length 4)])
+
+(define_insn *cset_zero
+ [(set (match_operand:SI 0 arith_reg_dest =r)
+ (if_then_else:SI (match_operand:SI 1 t_reg_operand)
+ (match_operand:SI 2 arith_reg_operand 0)
+ (const_int 0)))]
+ TARGET_SH1 TARGET_ZDCBRANCH
+{
+ return bt 0f \n
+ mov #0,%0 \n
+ 0:;
+}
+ [(set_attr type arith) ;; poor approximation
+ (set_attr length 4)])
+
(define_expand cstoresf4
[(set (match_operand:SI 0 register_operand =r)
(match_operator:SI 1 sh_float_comparison_operator
Index: gcc/testsuite/gcc.target/sh/pr51244-11.c
===
--- gcc/testsuite/gcc.target/sh/pr51244-11.c (revision 0)
+++ gcc/testsuite/gcc.target/sh/pr51244-11.c (revision 0)
@@ -0,0 +1,24 @@
+/* Check that zero-displacement branches are used instead of branch-free
+ execution patterns. */
+/* { dg-do compile { target sh*-*-* } } */
+/* { dg-options -O1 -mzdcbranch } */
+/* { dg-skip-if { sh*-*-* } { -m5* } { } } */
+/* { dg-final { scan-assembler-not subc|and } } */
+
+int*
+test_00 (int* s)
+{
+ if (s[0] == 0)
+if (!s[3])
+ s = 0;
+ return s;
+}
+
+int*
+test_01 (int* s)
+{
+ if (s[0] == 0)
+if (s[3])
+ s = 0;
+ return s;
+}
