Re: [PATCH] Improve add/sub TImode double word splitters (PR rtl-optimization/70467)

[Jakub Jelinek <jakub at redhat dot com>]

On Fri, Apr 01, 2016 at 08:29:17PM +0200, Uros Bizjak wrote:
> > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for stage1
> > (while the previous patch looks simple enough that I'd like to see it in
> > 6.x, this one IMHO can wait).
> 
> Yes, please. This is not a regression.
> 
> > 2016-04-01  Jakub Jelinek  <jakub@redhat.com>
> >
> >         PR rtl-optimization/70467
> >         * config/i386/predicates.md (x86_64_double_int_operand,
> >         x86_64_double_general_operand): New predicates.
> >         * config/i386/constraints.md (Wd): New constraint.
> >         * config/i386/i386.md (mode attr di): Use Wd instead of e.
> >         (double_general_operand): New mode attr.
> >         (add<mode>3, sub<mode>3): Use <double_general_operand>
> >         instead of <general_operand>.
> >         (*add<dwi>3_doubleword, *sub<dwi>3_doubleword): Use
> >         x86_64_double_general_operand instead of <general_operand>.
> >
> >         * gcc.target/i386/pr70467-3.c: New test.
> >         * gcc.target/i386/pr70467-4.c: New test.
> 
> OK.

Here is what I've committed after another bootstrap/regtest on x86_64-linux
and i686-linux.

2016-05-03  Jakub Jelinek  <jakub@redhat.com>
	    Uros Bizjak  <ubizjak@gmail.com>

	PR rtl-optimization/70467
	* config/i386/predicates.md (x86_64_hilo_int_operand,
	x86_64_hilo_general_operand): New predicates.
	* config/i386/constraints.md (Wd): New constraint.
	* config/i386/i386.md (mode attr di): Use Wd instead of e.
	(general_hilo_operand): New mode attr.
	(add<mode>3, sub<mode>3): Use <general_hilo_operand>
	instead of <general_operand>.
	(*add<dwi>3_doubleword, *sub<dwi>3_doubleword): Use
	x86_64_hilo_general_operand instead of <general_operand>.

	* gcc.target/i386/pr70467-3.c: New test.
	* gcc.target/i386/pr70467-4.c: New test.

--- gcc/config/i386/predicates.md.jj	2016-05-03 10:14:59.984142055 +0200
+++ gcc/config/i386/predicates.md	2016-05-03 10:45:21.478407060 +0200
@@ -342,6 +342,29 @@ (define_predicate "x86_64_zext_immediate
   return false;
 })
 
+;; Return true if VALUE is a constant integer whose low and high words satisfy
+;; x86_64_immediate_operand.
+(define_predicate "x86_64_hilo_int_operand"
+  (match_code "const_int,const_wide_int")
+{
+  switch (GET_CODE (op))
+    {
+    case CONST_INT:
+      return x86_64_immediate_operand (op, mode);
+
+    case CONST_WIDE_INT:
+      gcc_assert (CONST_WIDE_INT_NUNITS (op) == 2);
+      return (x86_64_immediate_operand (GEN_INT (CONST_WIDE_INT_ELT (op, 0)),
+					DImode)
+	      && x86_64_immediate_operand (GEN_INT (CONST_WIDE_INT_ELT (op,
+									1)),
+					   DImode));
+
+    default:
+      gcc_unreachable ();
+    }
+})
+
 ;; Return true if size of VALUE can be stored in a sign
 ;; extended immediate field.
 (define_predicate "x86_64_immediate_size_operand"
@@ -357,6 +380,14 @@ (define_predicate "x86_64_general_operan
 	 (match_operand 0 "x86_64_immediate_operand"))
     (match_operand 0 "general_operand")))
 
+;; Return true if OP's both words are general operands representable
+;; on x86_64.
+(define_predicate "x86_64_hilo_general_operand"
+  (if_then_else (match_test "TARGET_64BIT")
+    (ior (match_operand 0 "nonimmediate_operand")
+	 (match_operand 0 "x86_64_hilo_int_operand"))
+    (match_operand 0 "general_operand")))
+
 ;; Return true if OP is non-VOIDmode general operand representable
 ;; on x86_64.  This predicate is used in sign-extending conversion
 ;; operations that require non-VOIDmode immediate operands.
--- gcc/config/i386/constraints.md.jj	2016-05-02 16:19:20.789186595 +0200
+++ gcc/config/i386/constraints.md	2016-05-03 10:22:37.639927315 +0200
@@ -270,6 +270,11 @@ (define_constraint "Wz"
   (and (match_operand 0 "x86_64_zext_immediate_operand")
        (match_test "GET_MODE (op) != VOIDmode")))
 
+(define_constraint "Wd"
+  "128-bit integer constant where both the high and low 64-bit word
+   of it satisfies the e constraint."
+  (match_operand 0 "x86_64_hilo_int_operand"))
+
 (define_constraint "Z"
   "32-bit unsigned integer constant, or a symbolic reference known
    to fit that range (for immediate operands in zero-extending x86-64
--- gcc/config/i386/i386.md.jj	2016-05-03 10:17:39.818971577 +0200
+++ gcc/config/i386/i386.md	2016-05-03 10:22:37.644927247 +0200
@@ -1065,7 +1065,7 @@ (define_mode_attr i [(QI "n") (HI "n") (
 (define_mode_attr g [(QI "qmn") (HI "rmn") (SI "rme") (DI "rme")])
 
 ;; Immediate operand constraint for double integer modes.
-(define_mode_attr di [(SI "nF") (DI "e")])
+(define_mode_attr di [(SI "nF") (DI "Wd")])
 
 ;; Immediate operand constraint for shifts.
 (define_mode_attr S [(QI "I") (HI "I") (SI "I") (DI "J") (TI "O")])
@@ -1078,6 +1078,15 @@ (define_mode_attr general_operand
 	 (DI "x86_64_general_operand")
 	 (TI "x86_64_general_operand")])
 
+;; General operand predicate for integer modes, where for TImode
+;; we need both words of the operand to be general operands.
+(define_mode_attr general_hilo_operand
+	[(QI "general_operand")
+	 (HI "general_operand")
+	 (SI "x86_64_general_operand")
+	 (DI "x86_64_general_operand")
+	 (TI "x86_64_hilo_general_operand")])
+
 ;; General sign extend operand predicate for integer modes,
 ;; which disallows VOIDmode operands and thus it is suitable
 ;; for use inside sign_extend.
@@ -5433,7 +5442,7 @@ (define_insn_and_split "*lea<mode>"
 (define_expand "add<mode>3"
   [(set (match_operand:SDWIM 0 "nonimmediate_operand")
 	(plus:SDWIM (match_operand:SDWIM 1 "nonimmediate_operand")
-		    (match_operand:SDWIM 2 "<general_operand>")))]
+		    (match_operand:SDWIM 2 "<general_hilo_operand>")))]
   ""
   "ix86_expand_binary_operator (PLUS, <MODE>mode, operands); DONE;")
 
@@ -5441,7 +5450,8 @@ (define_insn_and_split "*add<dwi>3_doubl
   [(set (match_operand:<DWI> 0 "nonimmediate_operand" "=r,o")
 	(plus:<DWI>
 	  (match_operand:<DWI> 1 "nonimmediate_operand" "%0,0")
-	  (match_operand:<DWI> 2 "<general_operand>" "ro<di>,r<di>")))
+	  (match_operand:<DWI> 2 "x86_64_hilo_general_operand"
+							"ro<di>,r<di>")))
    (clobber (reg:CC FLAGS_REG))]
   "ix86_binary_operator_ok (PLUS, <DWI>mode, operands)"
   "#"
@@ -6345,7 +6355,7 @@ (define_insn_and_split "*lea<mode>_gener
 (define_expand "sub<mode>3"
   [(set (match_operand:SDWIM 0 "nonimmediate_operand")
 	(minus:SDWIM (match_operand:SDWIM 1 "nonimmediate_operand")
-		     (match_operand:SDWIM 2 "<general_operand>")))]
+		     (match_operand:SDWIM 2 "<general_hilo_operand>")))]
   ""
   "ix86_expand_binary_operator (MINUS, <MODE>mode, operands); DONE;")
 
@@ -6353,7 +6363,8 @@ (define_insn_and_split "*sub<dwi>3_doubl
   [(set (match_operand:<DWI> 0 "nonimmediate_operand" "=r,o")
 	(minus:<DWI>
 	  (match_operand:<DWI> 1 "nonimmediate_operand" "0,0")
-	  (match_operand:<DWI> 2 "<general_operand>" "ro<di>,r<di>")))
+	  (match_operand:<DWI> 2 "x86_64_hilo_general_operand"
+							"ro<di>,r<di>")))
    (clobber (reg:CC FLAGS_REG))]
   "ix86_binary_operator_ok (MINUS, <MODE>mode, operands)"
   "#"
--- gcc/testsuite/gcc.target/i386/pr70467-3.c.jj	2016-04-01 12:39:53.613101661 +0200
+++ gcc/testsuite/gcc.target/i386/pr70467-3.c	2016-04-01 12:44:30.747330485 +0200
@@ -0,0 +1,19 @@
+/* PR rtl-optimization/70467 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2" } */
+
+__uint128_t
+foo (__uint128_t x)
+{
+  return x + ((__uint128_t) 123456 << 64);
+}
+
+__uint128_t
+bar (__uint128_t x)
+{
+  return x - ((__uint128_t) 123456 << 64);
+}
+
+/* Make sure there are no unnecessary additions with carry.  */
+/* { dg-final { scan-assembler-not "adcq\[^\n\r\]*%" } } */
+/* { dg-final { scan-assembler-not "sbbq\[^\n\r\]*%" } } */
--- gcc/testsuite/gcc.target/i386/pr70467-4.c.jj	2016-04-01 12:40:01.567993391 +0200
+++ gcc/testsuite/gcc.target/i386/pr70467-4.c	2016-04-01 12:43:58.067775153 +0200
@@ -0,0 +1,18 @@
+/* PR rtl-optimization/70467 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2" } */
+
+__uint128_t
+foo (__uint128_t x)
+{
+  return x + ((__uint128_t) 123456 << 64) + 0x1234567;
+}
+
+__uint128_t
+bar (__uint128_t x)
+{
+  return x - ((__uint128_t) 123456 << 64) + 0x1234567;
+}
+
+/* Make sure the immediates are not loaded into registers first.  */
+/* { dg-final { scan-assembler-not "mov\[lq\]\[ \t\]*.\[0-9-\]" } } */


	Jakub