From: Richard Henderson <rth@redhat.com>
Date: Sun, 12 Sep 2004 18:00:49 +0000 (-0700)
Subject: i386.c (ix86_split_ashldi): Special case op1 as one or minus one.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=93330ea10a357abf2055c883935abf71102cbbec;p=gcc.git

i386.c (ix86_split_ashldi): Special case op1 as one or minus one.

        * config/i386/i386.c (ix86_split_ashldi): Special case op1 as one
        or minus one.
        (ix86_split_ashrdi, ix86_split_lshrdi): Clean up conditions for
        post-reload, and scratch NULL.
        * config/i386/i386.md (testqi_1): Use FLAGS_REG name.
        (x86_shift_adj_2): Use ix86_expand_clear.
        (ashldi3): Remove CMOVE expansion difference.
        (ashldi3_1): Remove.
        (*ashldi3_1): Rename from *ashldi3_2.  Use reg_or_pm1_operand and
        add constraints for immediates.  New peephole for split-with-temp.
        Run splitter after peep2 pass.
        (ashrdi3, ashrdi3_1, ashrdi3_2): Similarly.
        (lshrdi3, lshrdi3_1, lshrdi3_2): Similarly.
        (setcc_2): Rename with *.
        * config/i386/predicates.md (reg_or_pm1_operand): New.
        (ashldi_input_operand): New.

From-SVN: r87398
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index df4dd94b39e..578495b5492 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,22 @@
+2004-09-12  Richard Henderson  <rth@redhat.com>
+
+	* config/i386/i386.c (ix86_split_ashldi): Special case op1 as one
+	or minus one.
+	(ix86_split_ashrdi, ix86_split_lshrdi): Clean up conditions for
+	post-reload, and scratch NULL.
+	* config/i386/i386.md (testqi_1): Use FLAGS_REG name.
+	(x86_shift_adj_2): Use ix86_expand_clear.
+	(ashldi3): Remove CMOVE expansion difference.
+	(ashldi3_1): Remove.
+	(*ashldi3_1): Rename from *ashldi3_2.  Use reg_or_pm1_operand and
+	add constraints for immediates.  New peephole for split-with-temp.
+	Run splitter after peep2 pass.
+	(ashrdi3, ashrdi3_1, ashrdi3_2): Similarly.
+	(lshrdi3, lshrdi3_1, lshrdi3_2): Similarly.
+	(setcc_2): Rename with *.
+	* config/i386/predicates.md (reg_or_pm1_operand): New.
+	(ashldi_input_operand): New.
+
 2004-09-12  Richard Henderson  <rth@redhat.com
 
 	* print-rtl.c (print_decl_name): New.
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index e034fa9ef4e..c1911092419 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -10019,30 +10019,88 @@ ix86_split_ashldi (rtx *operands, rtx scratch)
 	  emit_insn (gen_x86_shld_1 (high[0], low[0], GEN_INT (count)));
 	  ix86_expand_ashlsi3_const (low[0], count);
 	}
+      return;
     }
-  else
+
+  split_di (operands, 1, low, high);
+
+  if (operands[1] == const1_rtx)
     {
-      if (!rtx_equal_p (operands[0], operands[1]))
-	emit_move_insn (operands[0], operands[1]);
+      /* Assuming we've chosen a QImode capable registers, then 1LL << N
+	 can be done with two 32-bit shifts, no branches, no cmoves.  */
+      if (ANY_QI_REG_P (low[0]) && ANY_QI_REG_P (high[0]))
+	{
+	  rtx s, d, flags = gen_rtx_REG (CCZmode, FLAGS_REG);
 
-      split_di (operands, 1, low, high);
+	  ix86_expand_clear (low[0]);
+	  ix86_expand_clear (high[0]);
+	  emit_insn (gen_testqi_ccz_1 (operands[2], GEN_INT (32)));
+	  
+	  d = gen_lowpart (QImode, low[0]);
+	  d = gen_rtx_STRICT_LOW_PART (VOIDmode, d);
+	  s = gen_rtx_EQ (QImode, flags, const0_rtx);
+	  emit_insn (gen_rtx_SET (VOIDmode, d, s));
 
-      emit_insn (gen_x86_shld_1 (high[0], low[0], operands[2]));
-      emit_insn (gen_ashlsi3 (low[0], low[0], operands[2]));
+	  d = gen_lowpart (QImode, high[0]);
+	  d = gen_rtx_STRICT_LOW_PART (VOIDmode, d);
+	  s = gen_rtx_NE (QImode, flags, const0_rtx);
+	  emit_insn (gen_rtx_SET (VOIDmode, d, s));
+	}
 
-      if (TARGET_CMOVE && (! no_new_pseudos || scratch))
+      /* Otherwise, we can get the same results by manually performing
+	 a bit extract operation on bit 5, and then performing the two
+	 shifts.  The two methods of getting 0/1 into low/high are exactly
+	 the same size.  Avoiding the shift in the bit extract case helps
+	 pentium4 a bit; no one else seems to care much either way.  */
+      else
 	{
-	  if (! no_new_pseudos)
-	    scratch = force_reg (SImode, const0_rtx);
+	  rtx x;
+
+	  if (TARGET_PARTIAL_REG_STALL && !optimize_size)
+	    x = gen_rtx_ZERO_EXTEND (SImode, operands[2]);
 	  else
-	    emit_move_insn (scratch, const0_rtx);
+	    x = gen_lowpart (SImode, operands[2]);
+	  emit_insn (gen_rtx_SET (VOIDmode, high[0], x));
 
-	  emit_insn (gen_x86_shift_adj_1 (high[0], low[0], operands[2],
-					  scratch));
+	  emit_insn (gen_lshrsi3 (high[0], high[0], GEN_INT (5)));
+	  emit_insn (gen_andsi3 (high[0], high[0], GEN_INT (1)));
+	  emit_move_insn (low[0], high[0]);
+	  emit_insn (gen_xorsi3 (low[0], low[0], GEN_INT (1)));
 	}
+
+      emit_insn (gen_ashlsi3 (low[0], low[0], operands[2]));
+      emit_insn (gen_ashlsi3 (high[0], high[0], operands[2]));
+      return;
+    }
+
+  if (operands[1] == constm1_rtx)
+    {
+      /* For -1LL << N, we can avoid the shld instruction, because we
+	 know that we're shifting 0...31 ones into a -1.  */
+      emit_move_insn (low[0], constm1_rtx);
+      if (optimize_size)
+        emit_move_insn (high[0], low[0]);
       else
-	emit_insn (gen_x86_shift_adj_2 (high[0], low[0], operands[2]));
+	emit_move_insn (high[0], constm1_rtx);
     }
+  else
+    {
+      if (!rtx_equal_p (operands[0], operands[1]))
+	emit_move_insn (operands[0], operands[1]);
+
+      split_di (operands, 1, low, high);
+      emit_insn (gen_x86_shld_1 (high[0], low[0], operands[2]));
+    }
+
+  emit_insn (gen_ashlsi3 (low[0], low[0], operands[2]));
+
+  if (TARGET_CMOVE && scratch)
+    {
+      ix86_expand_clear (scratch);
+      emit_insn (gen_x86_shift_adj_1 (high[0], low[0], operands[2], scratch));
+    }
+  else
+    emit_insn (gen_x86_shift_adj_2 (high[0], low[0], operands[2]));
 }
 
 void
@@ -10066,15 +10124,8 @@ ix86_split_ashrdi (rtx *operands, rtx scratch)
       else if (count >= 32)
 	{
 	  emit_move_insn (low[0], high[1]);
-
-	  if (! reload_completed)
-	    emit_insn (gen_ashrsi3 (high[0], low[0], GEN_INT (31)));
-	  else
-	    {
-	      emit_move_insn (high[0], low[0]);
-	      emit_insn (gen_ashrsi3 (high[0], high[0], GEN_INT (31)));
-	    }
-
+	  emit_move_insn (high[0], low[0]);
+	  emit_insn (gen_ashrsi3 (high[0], high[0], GEN_INT (31)));
 	  if (count > 32)
 	    emit_insn (gen_ashrsi3 (low[0], low[0], GEN_INT (count - 32)));
 	}
@@ -10096,10 +10147,8 @@ ix86_split_ashrdi (rtx *operands, rtx scratch)
       emit_insn (gen_x86_shrd_1 (low[0], high[0], operands[2]));
       emit_insn (gen_ashrsi3 (high[0], high[0], operands[2]));
 
-      if (TARGET_CMOVE && (! no_new_pseudos || scratch))
+      if (TARGET_CMOVE && scratch)
 	{
-	  if (! no_new_pseudos)
-	    scratch = gen_reg_rtx (SImode);
 	  emit_move_insn (scratch, high[0]);
 	  emit_insn (gen_ashrsi3 (scratch, scratch, GEN_INT (31)));
 	  emit_insn (gen_x86_shift_adj_1 (low[0], high[0], operands[2],
@@ -10124,7 +10173,7 @@ ix86_split_lshrdi (rtx *operands, rtx scratch)
       if (count >= 32)
 	{
 	  emit_move_insn (low[0], high[1]);
-	  emit_move_insn (high[0], const0_rtx);
+	  ix86_expand_clear (high[0]);
 
 	  if (count > 32)
 	    emit_insn (gen_lshrsi3 (low[0], low[0], GEN_INT (count - 32)));
@@ -10148,13 +10197,9 @@ ix86_split_lshrdi (rtx *operands, rtx scratch)
       emit_insn (gen_lshrsi3 (high[0], high[0], operands[2]));
 
       /* Heh.  By reversing the arguments, we can reuse this pattern.  */
-      if (TARGET_CMOVE && (! no_new_pseudos || scratch))
+      if (TARGET_CMOVE && scratch)
 	{
-	  if (! no_new_pseudos)
-	    scratch = force_reg (SImode, const0_rtx);
-	  else
-	    emit_move_insn (scratch, const0_rtx);
-
+	  ix86_expand_clear (scratch);
 	  emit_insn (gen_x86_shift_adj_1 (low[0], high[0], operands[2],
 					  scratch));
 	}
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 8ec7719b660..f2f3fbedbdf 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -1906,7 +1906,7 @@
 (define_split
   [(set (match_operand:DI 0 "push_operand" "")
         (match_operand:DI 1 "immediate_operand" ""))]
-  "TARGET_64BIT && (flow2_completed || (reload_completed && !flag_peephole2))
+  "TARGET_64BIT && (flag_peephole2 ? flow2_completed : reload_completed)
    && !symbolic_operand (operands[1], DImode)
    && !x86_64_immediate_operand (operands[1], DImode)"
   [(set (match_dup 0) (match_dup 1))
@@ -2168,7 +2168,7 @@
 (define_split
   [(set (match_operand:DI 0 "memory_operand" "")
         (match_operand:DI 1 "immediate_operand" ""))]
-  "TARGET_64BIT && (flow2_completed || (reload_completed && !flag_peephole2))
+  "TARGET_64BIT && (flag_peephole2 ? flow2_completed : reload_completed)
    && !symbolic_operand (operands[1], DImode)
    && !x86_64_immediate_operand (operands[1], DImode)"
   [(set (match_dup 2) (match_dup 3))
@@ -7924,7 +7924,7 @@
   "")
 
 (define_insn "*testqi_1"
-  [(set (reg 17)
+  [(set (reg FLAGS_REG)
         (compare (and:QI (match_operand:QI 0 "nonimmediate_operand" "%!*a,q,qm,r")
 			 (match_operand:QI 1 "general_operand" "n,n,qn,n"))
 		 (const_int 0)))]
@@ -10623,20 +10623,11 @@
 ;; than 31.
 
 (define_expand "ashldi3"
-  [(parallel [(set (match_operand:DI 0 "shiftdi_operand" "")
-		   (ashift:DI (match_operand:DI 1 "shiftdi_operand" "")
-			      (match_operand:QI 2 "nonmemory_operand" "")))
-	      (clobber (reg:CC FLAGS_REG))])]
+  [(set (match_operand:DI 0 "shiftdi_operand" "")
+	(ashift:DI (match_operand:DI 1 "ashldi_input_operand" "")
+		   (match_operand:QI 2 "nonmemory_operand" "")))]
   ""
-{
-  if (!TARGET_64BIT && TARGET_CMOVE && ! immediate_operand (operands[2], QImode))
-    {
-      emit_insn (gen_ashldi3_1 (operands[0], operands[1], operands[2]));
-      DONE;
-    }
-  ix86_expand_binary_operator (ASHIFT, DImode, operands);
-  DONE;
-})
+  "ix86_expand_binary_operator (ASHIFT, DImode, operands); DONE;")
 
 (define_insn "*ashldi3_1_rex64"
   [(set (match_operand:DI 0 "nonimmediate_operand" "=rm,r")
@@ -10738,41 +10729,35 @@
 	   (const_string "ishift")))
    (set_attr "mode" "DI")])
 
-(define_insn "ashldi3_1"
-  [(set (match_operand:DI 0 "register_operand" "=r")
-	(ashift:DI (match_operand:DI 1 "register_operand" "0")
-		   (match_operand:QI 2 "nonmemory_operand" "Jc")))
-   (clobber (match_scratch:SI 3 "=&r"))
-   (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && TARGET_CMOVE"
-  "#"
-  [(set_attr "type" "multi")])
-
-(define_insn "*ashldi3_2"
-  [(set (match_operand:DI 0 "register_operand" "=r")
-	(ashift:DI (match_operand:DI 1 "register_operand" "0")
-		   (match_operand:QI 2 "nonmemory_operand" "Jc")))
+(define_insn "*ashldi3_1"
+  [(set (match_operand:DI 0 "register_operand" "=&r,r")
+	(ashift:DI (match_operand:DI 1 "reg_or_pm1_operand" "n,0")
+		   (match_operand:QI 2 "nonmemory_operand" "Jc,Jc")))
    (clobber (reg:CC FLAGS_REG))]
   "!TARGET_64BIT"
   "#"
   [(set_attr "type" "multi")])
 
-(define_split
-  [(set (match_operand:DI 0 "register_operand" "")
-	(ashift:DI (match_operand:DI 1 "register_operand" "")
-		   (match_operand:QI 2 "nonmemory_operand" "")))
-   (clobber (match_scratch:SI 3 ""))
-   (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && TARGET_CMOVE && reload_completed"
+;; By default we don't ask for a scratch register, because when DImode
+;; values are manipulated, registers are already at a premium.  But if
+;; we have one handy, we won't turn it away.
+(define_peephole2
+  [(match_scratch:SI 3 "r")
+   (parallel [(set (match_operand:DI 0 "register_operand" "")
+		   (ashift:DI (match_operand:DI 1 "nonmemory_operand" "")
+			      (match_operand:QI 2 "nonmemory_operand" "")))
+	      (clobber (reg:CC FLAGS_REG))])
+   (match_dup 3)]
+  "!TARGET_64BIT && TARGET_CMOVE"
   [(const_int 0)]
   "ix86_split_ashldi (operands, operands[3]); DONE;")
 
 (define_split
   [(set (match_operand:DI 0 "register_operand" "")
-	(ashift:DI (match_operand:DI 1 "register_operand" "")
+	(ashift:DI (match_operand:DI 1 "nonmemory_operand" "")
 		   (match_operand:QI 2 "nonmemory_operand" "")))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && reload_completed"
+  "!TARGET_64BIT && (flag_peephole2 ? flow2_completed : reload_completed)"
   [(const_int 0)]
   "ix86_split_ashldi (operands, NULL_RTX); DONE;")
 
@@ -10829,7 +10814,7 @@
   JUMP_LABEL (tmp) = label;
 
   emit_move_insn (operands[0], operands[1]);
-  emit_move_insn (operands[1], const0_rtx);
+  ix86_expand_clear (operands[1]);
 
   emit_label (label);
   LABEL_NUSES (label) = 1;
@@ -11346,27 +11331,19 @@
 ;; See comment above `ashldi3' about how this works.
 
 (define_expand "ashrdi3"
-  [(parallel [(set (match_operand:DI 0 "shiftdi_operand" "")
-		   (ashiftrt:DI (match_operand:DI 1 "shiftdi_operand" "")
-				(match_operand:QI 2 "nonmemory_operand" "")))
-	      (clobber (reg:CC FLAGS_REG))])]
+  [(set (match_operand:DI 0 "shiftdi_operand" "")
+	(ashiftrt:DI (match_operand:DI 1 "shiftdi_operand" "")
+		     (match_operand:QI 2 "nonmemory_operand" "")))]
   ""
-{
-  if (!TARGET_64BIT && TARGET_CMOVE && ! immediate_operand (operands[2], QImode))
-    {
-      emit_insn (gen_ashrdi3_1 (operands[0], operands[1], operands[2]));
-      DONE;
-    }
-  ix86_expand_binary_operator (ASHIFTRT, DImode, operands);
-  DONE;
-})
+  "ix86_expand_binary_operator (ASHIFTRT, DImode, operands); DONE;")
 
-(define_insn "ashrdi3_63_rex64"
+(define_insn "*ashrdi3_63_rex64"
   [(set (match_operand:DI 0 "nonimmediate_operand" "=*d,rm")
 	(ashiftrt:DI (match_operand:DI 1 "nonimmediate_operand" "*a,0")
 		     (match_operand:DI 2 "const_int_operand" "i,i")))
    (clobber (reg:CC FLAGS_REG))]
-  "TARGET_64BIT && INTVAL (operands[2]) == 63 && (TARGET_USE_CLTD || optimize_size)
+  "TARGET_64BIT && INTVAL (operands[2]) == 63
+   && (TARGET_USE_CLTD || optimize_size)
    && ix86_binary_operator_ok (ASHIFTRT, DImode, operands)"
   "@
    {cqto|cqo}
@@ -11441,18 +11418,7 @@
   [(set_attr "type" "ishift")
    (set_attr "mode" "DI")])
 
-
-(define_insn "ashrdi3_1"
-  [(set (match_operand:DI 0 "register_operand" "=r")
-	(ashiftrt:DI (match_operand:DI 1 "register_operand" "0")
-		     (match_operand:QI 2 "nonmemory_operand" "Jc")))
-   (clobber (match_scratch:SI 3 "=&r"))
-   (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && TARGET_CMOVE"
-  "#"
-  [(set_attr "type" "multi")])
-
-(define_insn "*ashrdi3_2"
+(define_insn "*ashrdi3_1"
   [(set (match_operand:DI 0 "register_operand" "=r")
 	(ashiftrt:DI (match_operand:DI 1 "register_operand" "0")
 		     (match_operand:QI 2 "nonmemory_operand" "Jc")))
@@ -11461,13 +11427,17 @@
   "#"
   [(set_attr "type" "multi")])
 
-(define_split
-  [(set (match_operand:DI 0 "register_operand" "")
-	(ashiftrt:DI (match_operand:DI 1 "register_operand" "")
-		     (match_operand:QI 2 "nonmemory_operand" "")))
-   (clobber (match_scratch:SI 3 ""))
-   (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && TARGET_CMOVE && reload_completed"
+;; By default we don't ask for a scratch register, because when DImode
+;; values are manipulated, registers are already at a premium.  But if
+;; we have one handy, we won't turn it away.
+(define_peephole2
+  [(match_scratch:SI 3 "r")
+   (parallel [(set (match_operand:DI 0 "register_operand" "")
+		   (ashiftrt:DI (match_operand:DI 1 "register_operand" "")
+			        (match_operand:QI 2 "nonmemory_operand" "")))
+	      (clobber (reg:CC FLAGS_REG))])
+   (match_dup 3)]
+  "!TARGET_64BIT && TARGET_CMOVE"
   [(const_int 0)]
   "ix86_split_ashrdi (operands, operands[3]); DONE;")
 
@@ -11476,7 +11446,7 @@
 	(ashiftrt:DI (match_operand:DI 1 "register_operand" "")
 		     (match_operand:QI 2 "nonmemory_operand" "")))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && reload_completed"
+  "!TARGET_64BIT && (flag_peephole2 ? flow2_completed : reload_completed)"
   [(const_int 0)]
   "ix86_split_ashrdi (operands, NULL_RTX); DONE;")
 
@@ -11858,20 +11828,11 @@
 ;; See comment above `ashldi3' about how this works.
 
 (define_expand "lshrdi3"
-  [(parallel [(set (match_operand:DI 0 "shiftdi_operand" "")
-		   (lshiftrt:DI (match_operand:DI 1 "shiftdi_operand" "")
-			        (match_operand:QI 2 "nonmemory_operand" "")))
-	      (clobber (reg:CC FLAGS_REG))])]
+  [(set (match_operand:DI 0 "shiftdi_operand" "")
+	(lshiftrt:DI (match_operand:DI 1 "shiftdi_operand" "")
+		     (match_operand:QI 2 "nonmemory_operand" "")))]
   ""
-{
-  if (!TARGET_64BIT && TARGET_CMOVE && ! immediate_operand (operands[2], QImode))
-    {
-      emit_insn (gen_lshrdi3_1 (operands[0], operands[1], operands[2]));
-      DONE;
-    }
-  ix86_expand_binary_operator (LSHIFTRT, DImode, operands);
-  DONE;
-})
+  "ix86_expand_binary_operator (LSHIFTRT, DImode, operands); DONE;")
 
 (define_insn "*lshrdi3_1_one_bit_rex64"
   [(set (match_operand:DI 0 "nonimmediate_operand" "=rm")
@@ -11937,17 +11898,7 @@
   [(set_attr "type" "ishift")
    (set_attr "mode" "DI")])
 
-(define_insn "lshrdi3_1"
-  [(set (match_operand:DI 0 "register_operand" "=r")
-	(lshiftrt:DI (match_operand:DI 1 "register_operand" "0")
-		     (match_operand:QI 2 "nonmemory_operand" "Jc")))
-   (clobber (match_scratch:SI 3 "=&r"))
-   (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && TARGET_CMOVE"
-  "#"
-  [(set_attr "type" "multi")])
-
-(define_insn "*lshrdi3_2"
+(define_insn "*lshrdi3_1"
   [(set (match_operand:DI 0 "register_operand" "=r")
 	(lshiftrt:DI (match_operand:DI 1 "register_operand" "0")
 		     (match_operand:QI 2 "nonmemory_operand" "Jc")))
@@ -11956,13 +11907,17 @@
   "#"
   [(set_attr "type" "multi")])
 
-(define_split 
-  [(set (match_operand:DI 0 "register_operand" "")
-	(lshiftrt:DI (match_operand:DI 1 "register_operand" "")
-		     (match_operand:QI 2 "nonmemory_operand" "")))
-   (clobber (match_scratch:SI 3 ""))
-   (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && TARGET_CMOVE && reload_completed"
+;; By default we don't ask for a scratch register, because when DImode
+;; values are manipulated, registers are already at a premium.  But if
+;; we have one handy, we won't turn it away.
+(define_peephole2
+  [(match_scratch:SI 3 "r")
+   (parallel [(set (match_operand:DI 0 "register_operand" "")
+		   (lshiftrt:DI (match_operand:DI 1 "register_operand" "")
+			        (match_operand:QI 2 "nonmemory_operand" "")))
+	      (clobber (reg:CC FLAGS_REG))])
+   (match_dup 3)]
+  "!TARGET_64BIT && TARGET_CMOVE"
   [(const_int 0)]
   "ix86_split_lshrdi (operands, operands[3]); DONE;")
 
@@ -11971,7 +11926,7 @@
 	(lshiftrt:DI (match_operand:DI 1 "register_operand" "")
 		     (match_operand:QI 2 "nonmemory_operand" "")))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_64BIT && reload_completed"
+  "!TARGET_64BIT && (flag_peephole2 ? flow2_completed : reload_completed)"
   [(const_int 0)]
   "ix86_split_lshrdi (operands, NULL_RTX); DONE;")
 
@@ -12840,7 +12795,7 @@
   [(set_attr "type" "setcc")
    (set_attr "mode" "QI")])
 
-(define_insn "setcc_2"
+(define_insn "*setcc_2"
   [(set (strict_low_part (match_operand:QI 0 "nonimmediate_operand" "+qm"))
 	(match_operator:QI 1 "ix86_comparison_operator"
 	  [(reg 17) (const_int 0)]))]
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 220b01c81cc..96be8b9bc67 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -553,12 +553,23 @@
   return op == const1_rtx || op == constm1_rtx;
 })
 
+;; True for registers, or 1 or -1.  Used to optimize double-word shifts.
+(define_predicate "reg_or_pm1_operand"
+  (ior (match_operand 0 "register_operand")
+       (and (match_code "const_int")
+	    (match_test "op == const1_rtx || op == constm1_rtx"))))
+
 ;; True if OP is acceptable as operand of DImode shift expander.
 (define_predicate "shiftdi_operand"
   (if_then_else (match_test "TARGET_64BIT")
     (match_operand 0 "nonimmediate_operand")
     (match_operand 0 "register_operand")))
 
+(define_predicate "ashldi_input_operand"
+  (if_then_else (match_test "TARGET_64BIT")
+    (match_operand 0 "nonimmediate_operand")
+    (match_operand 0 "reg_or_pm1_operand")))
+
 ;; Return true if OP is a vector load from the constant pool with just
 ;; the first element non-zero.
 (define_predicate "zero_extended_scalar_load_operand"