From patchwork Mon Apr 30 17:14:34 2012
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Subject: Improve andq $0xffffffff, %reg handling (PR target/53110)
Date: Mon, 30 Apr 2012 07:14:34 -0000
From: Uros Bizjak <ubizjak@gmail.com>
X-Patchwork-Id: 155926
Message-Id: <CAFULd4ZEe1WW2cgd7_ENoF-BviuOH65ArX1nFqP9e0SyxiQs3w@mail.gmail.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Richard Henderson <rth@redhat.com>, gcc-patches@gcc.gnu.org

On Mon, Apr 30, 2012 at 3:10 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Mon, Apr 30, 2012 at 02:54:05PM +0200, Uros Bizjak wrote:
>> > My recent changes to zero_extend expanders should handle this
>> > automatically, and will undo generation of zero_extend pattern. Please
>> > see zero_extend<mode>si2_and expander, and how it handles
>> > TARGET_ZERO_EXTEND_WITH_AND targets.
>>
>> Attached patch implements this idea. In addition, it fixes the
>> splitter to not change output mode of zero_extension from HImode and
>> QImode from DImode to SImode. Although they generate the same
>> instruction, I think we should better keep original mode here.
>
> Thanks.  I was trying this morning slightly different patch for the same,
> but strangely it failed bootstrap, and didn't get around to analysing
> why a mem store had (zero_extend (subreg (reg))) on a RHS.
>
>> +  operands[1] = gen_lowpart (mode, operands[1]);
>> +
>> +  if (GET_MODE (operands[0]) == DImode)
>> +    insn = (mode == SImode)
>> +        ? gen_zero_extendsidi2
>> +        : (mode == HImode)
>> +        ? gen_zero_extendhidi2
>> +        : gen_zero_extendqidi2;
>> +  else if (GET_MODE (operands[0]) == SImode)
>> +    insn = (mode == HImode)
>> +        ? gen_zero_extendhisi2
>> +        : gen_zero_extendqisi2;
>> +  else if (GET_MODE (operands[0]) == HImode)
>> +    insn = gen_zero_extendqihi2;
>>    else
>> -    ix86_expand_binary_operator (AND, <MODE>mode, operands);
>> +    gcc_unreachable ();
>> +
>> +  emit_insn (insn (operands[0], operands[1]));
>
> IMHO you should use <MODE>mode instead of GET_MODE (operands[0])
> in all of the above, then the compiler can actually optimize
> it at compile time.

2012-04-30  Uros Bizjak  <ubizjak@gmail.com>

	* config/i386/i386.md (and<mode>3): Change runtime operand mode checks
	to compile-time "mode == <MODE>mode" checks.
	(and splitter): Ditto.

Tested on x86_64-pc-linux-gnu, committed to mainline SVN.

Uros.


Index: config/i386/i386.md
===================================================================
--- config/i386/i386.md	(revision 186992)
+++ config/i386/i386.md	(working copy)
@@ -7695,7 +7695,7 @@
 		  (match_operand:SWIM 2 "<general_szext_operand>")))]
   ""
 {
-  enum machine_mode mode = GET_MODE (operands[1]);
+  enum machine_mode mode = <MODE>mode;
   rtx (*insn) (rtx, rtx);
 
   if (CONST_INT_P (operands[2]) && REG_P (operands[0]))
@@ -7710,30 +7710,28 @@
 	mode = QImode;
       }
 
-  if (mode == GET_MODE (operands[1]))
+  if (mode == <MODE>mode)
     {
       ix86_expand_binary_operator (AND, <MODE>mode, operands);
       DONE;
     }
 
-  operands[1] = gen_lowpart (mode, operands[1]);
-
-  if (GET_MODE (operands[0]) == DImode)
+  if (<MODE>mode == DImode)
     insn = (mode == SImode)
 	   ? gen_zero_extendsidi2
 	   : (mode == HImode)
 	   ? gen_zero_extendhidi2
 	   : gen_zero_extendqidi2;
-  else if (GET_MODE (operands[0]) == SImode)
+  else if (<MODE>mode == SImode)
     insn = (mode == HImode)
 	   ? gen_zero_extendhisi2
 	   : gen_zero_extendqisi2;
-  else if (GET_MODE (operands[0]) == HImode)
+  else if (<MODE>mode == HImode)
     insn = gen_zero_extendqihi2;
   else
     gcc_unreachable ();
 
-  emit_insn (insn (operands[0], operands[1]));
+  emit_insn (insn (operands[0], gen_lowpart (mode, operands[1])));
   DONE;
 })
 
@@ -7884,9 +7882,7 @@
       mode = QImode;
     }
 
-  operands[1] = gen_lowpart (mode, operands[1]);
-
-  if (GET_MODE (operands[0]) == DImode)
+  if (<MODE>mode == DImode)
     insn = (mode == SImode)
 	   ? gen_zero_extendsidi2
 	   : (mode == HImode)
@@ -7894,14 +7890,15 @@
 	   : gen_zero_extendqidi2;
   else
     {
-      /* Zero extend to SImode to avoid partial register stalls.  */
-      operands[0] = gen_lowpart (SImode, operands[0]);
+      if (<MODE>mode != SImode)
+	/* Zero extend to SImode to avoid partial register stalls.  */
+	operands[0] = gen_lowpart (SImode, operands[0]);
 
       insn = (mode == HImode)
 	     ? gen_zero_extendhisi2
 	     : gen_zero_extendqisi2;
     }
-  emit_insn (insn (operands[0], operands[1]));
+  emit_insn (insn (operands[0], gen_lowpart (mode, operands[1])));
   DONE;
 })