[SH] PR 51244 - Improve T bit to reg store

[SH] PR 51244 - Improve T bit to reg store

[Oleg Endo]

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Hello,

This improves some cases where the T bit is stored as all ones or all
zeros to a GP reg.
Tested on rev 189916 with
make -k check RUNTESTFLAGS="--target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a/-mb,-m2a-single/-mb,-m4/-ml,-m4/-mb,
-m4-single/-ml,-m4-single/-mb,-m4a-single/-ml,-m4a-single/-mb}"

and no new failures.
OK?

Cheers,
Oleg

ChangeLog:
	PR target/51244
	* config/sh/sh.md (mov_neg_si_t): Move to Scc instructions
	section.
	Use t_reg_operand predicate.  Add split for negated case.
	(ashrsi2_31): Pass get_t_reg_rtx to gen_mov_neg_si_t.
	* config/sh/sh.c (expand_ashiftrt): Likewise.

testsuite/ChangeLog:
	PR target/51244
	* gcc.target/sh/pr51244-4.c: New.

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Index: gcc/config/sh/sh.c
===================================================================
--- gcc/config/sh/sh.c	(revision 189917)
+++ gcc/config/sh/sh.c	(working copy)
@@ -3481,7 +3481,7 @@
 	{
 	  emit_insn (gen_cmpgtsi_t (force_reg (SImode, CONST0_RTX (SImode)),
 				    operands[1]));
-	  emit_insn (gen_mov_neg_si_t (operands[0]));
+	  emit_insn (gen_mov_neg_si_t (operands[0], get_t_reg_rtx ()));
 	  return true;
 	}
       emit_insn (gen_ashrsi2_31 (operands[0], operands[1]));
Index: gcc/config/sh/sh.md
===================================================================
--- gcc/config/sh/sh.md	(revision 189916)
+++ gcc/config/sh/sh.md	(working copy)
@@ -1584,15 +1584,6 @@
   "subc	%2,%0"
   [(set_attr "type" "arith")])
 
-;; life_analysis thinks rn is live before subc rn,rn, so make a special
-;; pattern for this case.  This helps multimedia applications that compute
-;; the sum of absolute differences.
-(define_insn "mov_neg_si_t"
-  [(set (match_operand:SI 0 "arith_reg_dest" "=r") (neg:SI (reg:SI T_REG)))]
-  "TARGET_SH1"
-  "subc	%0,%0"
-  [(set_attr "type" "arith")])
-
 (define_insn "*subsi3_internal"
   [(set (match_operand:SI 0 "arith_reg_dest" "=r")
 	(minus:SI (match_operand:SI 1 "arith_reg_operand" "0")
@@ -3797,7 +3788,7 @@
   [(const_int 0)]
 {
   emit_insn (gen_ashlsi_c (operands[0], operands[1]));
-  emit_insn (gen_mov_neg_si_t (copy_rtx (operands[0])));
+  emit_insn (gen_mov_neg_si_t (operands[0], get_t_reg_rtx ()));
   DONE;
 })
 
@@ -9704,6 +9695,25 @@
   ""
   [(const_int 0)])
 
+;; Store T bit as all zeros or ones in a reg.
+(define_insn "mov_neg_si_t"
+  [(set (match_operand:SI 0 "arith_reg_dest" "=r")
+	(neg:SI (match_operand 1 "t_reg_operand" "")))]
+  "TARGET_SH1"
+  "subc	%0,%0"
+  [(set_attr "type" "arith")])
+
+;; Store negated T bit as all zeros or ones in a reg.
+;; Use the following sequence:
+;; 	subc	Rn,Rn	! Rn = Rn - Rn - T; T = T
+;;	not	Rn,Rn	! Rn = 0 - Rn
+(define_split
+  [(set (match_operand:SI 0 "arith_reg_dest" "")
+	(neg:SI (match_operand 1 "negt_reg_operand" "")))]
+  "TARGET_SH1"
+  [(set (match_dup 0) (neg:SI (reg:SI T_REG)))
+   (set (match_dup 0) (not:SI (match_dup 0)))])
+
 ;; The *movtt pattern eliminates redundant T bit to T bit moves / tests.
 (define_insn_and_split "*movtt"
   [(set (reg:SI T_REG)
Index: gcc/testsuite/gcc.target/sh/pr51244-4.c
===================================================================
--- gcc/testsuite/gcc.target/sh/pr51244-4.c	(revision 0)
+++ gcc/testsuite/gcc.target/sh/pr51244-4.c	(revision 0)
@@ -0,0 +1,19 @@
+/* Check that storing the (negated) T bit as all ones or zeros in a reg
+   uses the subc instruction.  On SH2A a sequence with the movrt instruction
+   is also OK instead of subc.  */
+/* { dg-do compile { target "sh*-*-*" } } */
+/* { dg-options "-O1 -mbranch-cost=2" } */
+/* { dg-skip-if "" { "sh*-*-*" } { "-m5*"} { "" } } */
+/* { dg-final { scan-assembler-not "movt|tst|negc" } } */
+/* { dg-final { scan-assembler "subc|movrt|neg|not" } } */
+
+int test_00 (int x, int y)
+{
+  return x != y ? -1 : 0;
+}
+
+int test_01 (int x, int y)
+{
+  return x == y ? -1 : 0;
+}
+

Re: [SH] PR 51244 - Improve T bit to reg store

[Kaz Kojima]

Oleg Endo <oleg.endo@t-online.de> wrote:
> This improves some cases where the T bit is stored as all ones or all
> zeros to a GP reg.
> Tested on rev 189916 with
> make -k check RUNTESTFLAGS="--target_board=sh-sim
> \{-m2/-ml,-m2/-mb,-m2a/-mb,-m2a-single/-mb,-m4/-ml,-m4/-mb,
> -m4-single/-ml,-m4-single/-mb,-m4a-single/-ml,-m4a-single/-mb}"
> 
> and no new failures.
> OK?

OK.

Regards,
	kaz