re PR target/52898 (SH Target: Inefficient DImode comparisons)

gcc/
	PR target/52898
	* config/sh/sh.c (sh_option_override): Remove TARGET_CBRANCHDI4,
	TARGET_CMPEQDI_T.
	(prepare_cbranch_operands): Don't use scratch register.  Assume that
	function is used when pseudos can be created.
	(expand_cbranchdi4): Likewise.  Remove unused TARGET_CMPEQDI_T paths.
	* config/sh/sh.md (cbranchsi4): Allow only when pseudos can be created.
	(cbranchdi4, cbranchdi4_i): Simplify to single cbranchdi4
	define_expand.  Allow it only when pseudos can be created.
	* config/sh/sh.opt (mcbranchdi, mcmpeqdi): Delete.

From-SVN: r235698

4 files changed, 26 insertions, 115 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3af200d..e88ca46 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2016-05-02  Oleg Endo  <olegendo@gcc.gnu.org>
+
+	PR target/52898
+	* config/sh/sh.c (sh_option_override): Remove TARGET_CBRANCHDI4,
+	TARGET_CMPEQDI_T.
+	(prepare_cbranch_operands): Don't use scratch register.  Assume that
+	function is used when pseudos can be created.
+	(expand_cbranchdi4): Likewise.  Remove unused TARGET_CMPEQDI_T paths.
+	* config/sh/sh.md (cbranchsi4): Allow only when pseudos can be created.
+	(cbranchdi4, cbranchdi4_i): Simplify to single cbranchdi4
+	define_expand.  Allow it only when pseudos can be created.
+	* config/sh/sh.opt (mcbranchdi, mcmpeqdi): Delete.
+
 2016-05-01  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/constraints.md (BC): Only allow -1 operands.
diff --git a/gcc/config/sh/sh.c b/gcc/config/sh/sh.c
index cddb31c..ebdb523 100644
--- a/gcc/config/sh/sh.c
+++ b/gcc/config/sh/sh.c
@@ -809,10 +809,6 @@ sh_option_override (void)
   if (optimize > 1 && !optimize_size)
     target_flags |= MASK_SAVE_ALL_TARGET_REGS;
 
-  /* Set default values of TARGET_CBRANCHDI4 and TARGET_CMPEQDI_T.  */
-  TARGET_CBRANCHDI4 = 1;
-  TARGET_CMPEQDI_T = 0;
-
   sh_cpu = PROCESSOR_SH1;
   assembler_dialect = 0;
   if (TARGET_SH2)
@@ -1936,24 +1932,17 @@ enum rtx_code
 prepare_cbranch_operands (rtx *operands, machine_mode mode,
 			  enum rtx_code comparison)
 {
-  /* The scratch reg is only available when this is invoked from within
-     the cbranchdi4_i splitter, through expand_cbranchdi4.  */
-  rtx scratch = NULL_RTX;
+  gcc_assert (can_create_pseudo_p ());
 
   if (comparison == LAST_AND_UNUSED_RTX_CODE)
     comparison = GET_CODE (operands[0]);
-  else
-    scratch = operands[4];
 
   sh_canonicalize_comparison (comparison, operands[1], operands[2],
 			      mode, false);
 
-  /* Notice that this function is also invoked after reload by
-     the cbranchdi4_i pattern, through expand_cbranchdi4.  */
   rtx op1 = operands[1];
+  operands[1] = force_reg (mode, op1);
 
-  if (can_create_pseudo_p ())
-    operands[1] = force_reg (mode, op1);
   /* When we are handling DImode comparisons, we want to keep constants so
      that we can optimize the component comparisons; however, memory loads
      are better issued as a whole so that they can be scheduled well.
@@ -1969,15 +1958,8 @@ prepare_cbranch_operands (rtx *operands, machine_mode mode,
 	      && ((comparison != EQ && comparison != NE)
 		  || (REG_P (op1) && REGNO (op1) != R0_REG)
 		  || !satisfies_constraint_I08 (operands[2])))))
-    {
-      if (scratch && GET_MODE (scratch) == mode)
-	{
-	  emit_move_insn (scratch, operands[2]);
-	  operands[2] = scratch;
-	}
-      else if (can_create_pseudo_p ())
-	operands[2] = force_reg (mode, operands[2]);
-    }
+    operands[2] = force_reg (mode, operands[2]);
+
   return comparison;
 }
 
@@ -2027,7 +2009,6 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
   int num_branches;
   int prob, rev_prob;
   int msw_taken_prob = -1, msw_skip_prob = -1, lsw_taken_prob = -1;
-  rtx scratch = operands[4];
 
   comparison = prepare_cbranch_operands (operands, DImode, comparison);
   op1h = gen_highpart_mode (SImode, DImode, operands[1]);
@@ -2039,17 +2020,7 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
   rev_prob = REG_BR_PROB_BASE - prob;
   switch (comparison)
     {
-    /* ??? Should we use the cmpeqdi_t pattern for equality comparisons?
-       That costs 1 cycle more when the first branch can be predicted taken,
-       but saves us mispredicts because only one branch needs prediction.
-       It also enables generating the cmpeqdi_t-1 pattern.  */
     case EQ:
-      if (TARGET_CMPEQDI_T)
-	{
-	  emit_insn (gen_cmpeqdi_t (operands[1], operands[2]));
-	  emit_jump_insn (gen_branch_true (operands[3]));
-	  return true;
-	}
       msw_skip = NE;
       lsw_taken = EQ;
       if (prob >= 0)
@@ -2070,12 +2041,6 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
 	}
       break;
     case NE:
-      if (TARGET_CMPEQDI_T)
-	{
-	  emit_insn (gen_cmpeqdi_t (operands[1], operands[2]));
-	  emit_jump_insn (gen_branch_false (operands[3]));
-	  return true;
-	}
       msw_taken = NE;
       msw_taken_prob = prob;
       lsw_taken = NE;
@@ -2152,15 +2117,7 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
   operands[1] = op1h;
   operands[2] = op2h;
   operands[4] = NULL_RTX;
-  if (reload_completed
-      && ! arith_reg_or_0_operand (op2h, SImode)
-      && (true_regnum (op1h) || (comparison != EQ && comparison != NE))
-      && (msw_taken != LAST_AND_UNUSED_RTX_CODE
-	  || msw_skip != LAST_AND_UNUSED_RTX_CODE))
-    {
-      emit_move_insn (scratch, operands[2]);
-      operands[2] = scratch;
-    }
+
   if (msw_taken != LAST_AND_UNUSED_RTX_CODE)
     expand_cbranchsi4 (operands, msw_taken, msw_taken_prob);
   if (msw_skip != LAST_AND_UNUSED_RTX_CODE)
@@ -2173,13 +2130,6 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
 	{
 	  operands[1] = op1h;
 	  operands[2] = op2h;
-	  if (reload_completed
-	      && ! arith_reg_or_0_operand (op2h, SImode)
-	      && (true_regnum (op1h) || (comparison != EQ && comparison != NE)))
-	    {
-	      emit_move_insn (scratch, operands[2]);
-	      operands[2] = scratch;
-	    }
 	}
 
       operands[3] = skip_label = gen_label_rtx ();
@@ -2189,16 +2139,7 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
   operands[1] = op1l;
   operands[2] = op2l;
   if (lsw_taken != LAST_AND_UNUSED_RTX_CODE)
-    {
-      if (reload_completed
-	  && ! arith_reg_or_0_operand (op2l, SImode)
-	  && (true_regnum (op1l) || (lsw_taken != EQ && lsw_taken != NE)))
-	{
-	  emit_move_insn (scratch, operands[2]);
-	  operands[2] = scratch;
-	}
-      expand_cbranchsi4 (operands, lsw_taken, lsw_taken_prob);
-    }
+    expand_cbranchsi4 (operands, lsw_taken, lsw_taken_prob);
   if (msw_skip != LAST_AND_UNUSED_RTX_CODE)
     emit_label (skip_label);
   return true;
diff --git a/gcc/config/sh/sh.md b/gcc/config/sh/sh.md
index bb97e2a..af46acc 100644
--- a/gcc/config/sh/sh.md
+++ b/gcc/config/sh/sh.md
@@ -1115,7 +1115,7 @@
 		      (label_ref (match_operand 3 "" ""))
 		      (pc)))
    (clobber (reg:SI T_REG))]
-  ""
+  "can_create_pseudo_p ()"
 {
   expand_cbranchsi4 (operands, LAST_AND_UNUSED_RTX_CODE, -1);
   DONE;
@@ -1161,7 +1161,8 @@
 			   (label_ref (match_dup 2))
 			   (pc)))])
 
-;; FIXME: These could probably use code iterators for the compare op.
+;; FIXME: These don't seem to have any effect on the generated cbranch code
+;;	  anymore, but only on some register allocation choices.
 (define_split
   [(set (pc)
 	(if_then_else (le (match_operand:SI 0 "arith_reg_operand" "")
@@ -1255,48 +1256,12 @@
 (define_expand "cbranchdi4"
   [(set (pc)
 	(if_then_else (match_operator 0 "comparison_operator"
-			[(match_operand:DI 1 "arith_operand" "")
-			 (match_operand:DI 2 "arith_operand" "")])
-		      (label_ref (match_operand 3 "" ""))
-		      (pc)))
-   (clobber (match_dup 4))
-   (clobber (reg:SI T_REG))]
-  "TARGET_CBRANCHDI4 || TARGET_SH2"
-{
-  enum rtx_code comparison;
-
-  if (!TARGET_CBRANCHDI4)
-    {
-      sh_emit_compare_and_branch (operands, DImode);
-      DONE;
-    }
-  else
-    {
-      if (expand_cbranchdi4 (operands, LAST_AND_UNUSED_RTX_CODE))
-	DONE;
-
-      comparison = prepare_cbranch_operands (operands, DImode,
-					     LAST_AND_UNUSED_RTX_CODE);
-      if (comparison != GET_CODE (operands[0]))
-	operands[0]
-	  = gen_rtx_fmt_ee (comparison, VOIDmode, operands[1], operands[2]);
-       operands[4] = gen_rtx_SCRATCH (SImode);
-    }
-})
-
-(define_insn_and_split "cbranchdi4_i"
-  [(set (pc)
-	(if_then_else (match_operator 0 "comparison_operator"
-			[(match_operand:DI 1 "arith_operand" "r,r")
-			 (match_operand:DI 2 "arith_operand" "rN,I08")])
-		      (label_ref (match_operand 3 "" ""))
+			[(match_operand:DI 1 "arith_operand")
+			 (match_operand:DI 2 "arith_operand")])
+		      (label_ref (match_operand 3))
 		      (pc)))
-   (clobber (match_scratch:SI 4 "=X,&r"))
    (clobber (reg:SI T_REG))]
-  "TARGET_CBRANCHDI4"
-  "#"
-  "&& reload_completed"
-  [(pc)]
+  "TARGET_SH2 && can_create_pseudo_p ()"
 {
   if (!expand_cbranchdi4 (operands, GET_CODE (operands[0])))
     FAIL;
diff --git a/gcc/config/sh/sh.opt b/gcc/config/sh/sh.opt
index a6b63dc..f9b02c5 100644
--- a/gcc/config/sh/sh.opt
+++ b/gcc/config/sh/sh.opt
@@ -205,14 +205,6 @@ mzdcbranch
 Target Report Var(TARGET_ZDCBRANCH)
 Assume that zero displacement conditional branches are fast.
 
-mcbranchdi
-Target Undocumented Var(TARGET_CBRANCHDI4) Warn(%qs is deprecated and has no effect)
-Enable cbranchdi4 pattern.
-
-mcmpeqdi
-Target Undocumented Var(TARGET_CMPEQDI_T) Warn(%qs is deprecated and has no effect)
-Emit cmpeqdi_t pattern even when -mcbranchdi is in effect.
-
 mcbranch-force-delay-slot
 Target Report RejectNegative Var(TARGET_CBRANCH_FORCE_DELAY_SLOT) Init(0)
 Force the usage of delay slots for conditional branches.