re PR target/51244 ([SH] Inefficient conditional branch and code around T bit)

	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.

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

From-SVN: r189953

5 files changed, 53 insertions, 11 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c734d93..4252084 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2012-07-30  Oleg Endo  <olegendo@gcc.gnu.org>
 
+	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.
+
+2012-07-30  Oleg Endo  <olegendo@gcc.gnu.org>
+
 	PR target/54089
 	* config/sh/sh.md (ashlsi3_d): Invoke gen_shifty_op directly instead
 	of trying to emit ashlsi3_n.
diff --git a/gcc/config/sh/sh.c b/gcc/config/sh/sh.c
index 8edbb34..88497c7 100644
--- a/gcc/config/sh/sh.c
+++ b/gcc/config/sh/sh.c
@@ -3481,7 +3481,7 @@ expand_ashiftrt (rtx *operands)
 	{
 	  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]));
diff --git a/gcc/config/sh/sh.md b/gcc/config/sh/sh.md
index b9be129..6382238 100644
--- a/gcc/config/sh/sh.md
+++ b/gcc/config/sh/sh.md
@@ -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")
@@ -3802,7 +3793,7 @@ label:
   [(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;
 })
 
@@ -9709,6 +9700,25 @@ label:
   ""
   [(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)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c318d45..74af965 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-07-30  Oleg Endo  <olegendo@gcc.gnu.org>
+
+	PR target/51244
+	* gcc.target/sh/pr51244-4.c: New.
+
 2012-07-27  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gfortran.dg/bind_c_array_params_2.f90: Add "-mno-explicit-relocs"
diff --git a/gcc/testsuite/gcc.target/sh/pr51244-4.c b/gcc/testsuite/gcc.target/sh/pr51244-4.c
new file mode 100644
index 0000000..f307378
--- /dev/null
+++ b/gcc/testsuite/gcc.target/sh/pr51244-4.c
@@ -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;
+}
+