diff mbox

PING: PATCH [4/n]: Prepare x32: Permute the conversion and addition if one operand is a constant

Message ID CAMe9rOqE4uOuhxBWF6a-ONrNEbQOW5h_sN9AZnFfD1NEnr1i7g@mail.gmail.com
State New
Headers show

Commit Message

H.J. Lu July 13, 2011, 5:48 p.m. UTC 
On Wed, Jul 13, 2011 at 9:54 AM, Paolo Bonzini <bonzini@gnu.org> wrote:
>>>> Why?  Certainly Y = 8 has 31-bit (or less) precision.  So it has the same
>>>> representation in SImode and DImode, and the test above on XEXP (x, 1)
>>>> succeeds.
>>>
>>> And then we permute conversion and addition, which leads to the issue you
>>> raised above.  In another word, the current code permutes conversion
>>> and addition.
>>
>> No, only if we have ptr_extend.
>
> Oops, hit send too early, I understand now what you mean.  But even
> more so, let's make sure x32 is done right so that perhaps we can
> remove the bogus test on XEXP (x, 1) for other Pmode != ptr_mode
> targets, non-ptr_extend.  Then we can worry perhaps of
> POINTERS_EXTEND_UNSIGNED < 0.
>

Here is the patch.  OK for trunk?

Thanks.

Comments

Paolo Bonzini July 25, 2011, 9:58 a.m. UTC | #1 
On 07/13/2011 07:48 PM, H.J. Lu wrote:
> Here is the patch.  OK for trunk?

Again, at least you should explain clearly _why_ you need 
ignore_address_wrap_around.  You said elsewhere x32 should be first 
clean, then fast.

>    if (GET_CODE (x) == SUBREG && SUBREG_PROMOTED_VAR_P (x)
>        && GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) >= GET_MODE_SIZE (mode)
>        && SUBREG_PROMOTED_UNSIGNED_P (x) == unsignedp)
> +    {
> +      if (no_emit)
> +	x = rtl_hooks.gen_lowpart_no_emit (mode, x);
> +      else
> +	x = gen_lowpart (mode, x);
> +    }
> @@ -773,7 +781,10 @@ convert_modes (enum machine_mode mode, enum machine_mode oldmode, rtx x, int uns
>  	  return gen_int_mode (val, mode);
>  	}
>
> -      return gen_lowpart (mode, x);
> +      if (no_emit)
> +	return rtl_hooks.gen_lowpart_no_emit (mode, x);
> +      else
> +	return gen_lowpart (mode, x);
>      }

These should be

   rtx tem = rtl_hooks.gen_lowpart_no_emit (mode, x);
   if (tem)
     x = tem;

   rtx tem = rtl_hooks.gen_lowpart_no_emit (mode, x);
   if (tem)
     return x;

since the "emitting" case can just reuse the code below.  However, see 
the patch I'm sending now.

Paolo
diff mbox

Patch

diff --git a/gcc/explow.c b/gcc/explow.c
index 3c692f4..8551fe8 100644
--- a/gcc/explow.c
+++ b/gcc/explow.c
@@ -320,8 +320,10 @@  break_out_memory_refs (rtx x)
    arithmetic insns can be used.  */
 
 rtx
-convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED,
-				   rtx x, addr_space_t as ATTRIBUTE_UNUSED)
+convert_memory_address_addr_space_1 (enum machine_mode to_mode ATTRIBUTE_UNUSED,
+				     rtx x, addr_space_t as ATTRIBUTE_UNUSED,
+				     bool no_emit ATTRIBUTE_UNUSED,
+				     bool ignore_address_wrap_around ATTRIBUTE_UNUSED)
 {
 #ifndef POINTERS_EXTEND_UNSIGNED
   gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
@@ -377,28 +379,28 @@  convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED,
       break;
 
     case CONST:
-      return gen_rtx_CONST (to_mode,
-			    convert_memory_address_addr_space
-			      (to_mode, XEXP (x, 0), as));
+      temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0),
+						  as, no_emit,
+						  ignore_address_wrap_around);
+      return temp ? gen_rtx_CONST (to_mode, temp) : temp;
       break;
 
     case PLUS:
     case MULT:
-      /* For addition we can safely permute the conversion and addition
-	 operation if one operand is a constant and converting the constant
-	 does not change it or if one operand is a constant and we are
-	 using a ptr_extend instruction  (POINTERS_EXTEND_UNSIGNED < 0).
-	 We can always safely permute them if we are making the address
-	 narrower.  */
+      /* For addition, we can safely permute the conversion and addition
+	 operation if one operand is a constant and we are using a
+	 ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0) or address
+	 wrap-around is ignored.  We can always safely permute them if
+	 we are making the address narrower.  */
       if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
 	  || (GET_CODE (x) == PLUS
 	      && CONST_INT_P (XEXP (x, 1))
-	      && (XEXP (x, 1) == convert_memory_address_addr_space
-				   (to_mode, XEXP (x, 1), as)
-                 || POINTERS_EXTEND_UNSIGNED < 0)))
+	      && (POINTERS_EXTEND_UNSIGNED < 0
+		  || ignore_address_wrap_around)))
 	return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
-			       convert_memory_address_addr_space
-				 (to_mode, XEXP (x, 0), as),
+			       convert_memory_address_addr_space_1
+				 (to_mode, XEXP (x, 0), as, no_emit,
+				  ignore_address_wrap_around),
 			       XEXP (x, 1));
       break;
 
@@ -406,10 +408,17 @@  convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED,
       break;
     }
 
-  return convert_modes (to_mode, from_mode,
-			x, POINTERS_EXTEND_UNSIGNED);
+  return convert_modes_1 (to_mode, from_mode, x,
+			  POINTERS_EXTEND_UNSIGNED, no_emit);
 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
 }
+
+rtx
+convert_memory_address_addr_space (enum machine_mode to_mode,
+				   rtx x, addr_space_t as)
+{
+  return convert_memory_address_addr_space_1 (to_mode, x, as, false, true);
+}
 
 /* Return something equivalent to X but valid as a memory address for something
    of mode MODE in the named address space AS.  When X is not itself valid,
diff --git a/gcc/expr.c b/gcc/expr.c
index 77039e8..e42ab04 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -693,13 +693,16 @@  convert_to_mode (enum machine_mode mode, rtx x, int unsignedp)
    Both modes may be floating, or both integer.
    UNSIGNEDP is nonzero if X is an unsigned value.
 
+   If NO_EMIT is true, don't emit any instructions.
+
    This can be done by referring to a part of X in place
    or by copying to a new temporary with conversion.
 
    You can give VOIDmode for OLDMODE, if you are sure X has a nonvoid mode.  */
 
 rtx
-convert_modes (enum machine_mode mode, enum machine_mode oldmode, rtx x, int unsignedp)
+convert_modes_1 (enum machine_mode mode, enum machine_mode oldmode,
+		 rtx x, int unsignedp, bool no_emit)
 {
   rtx temp;
 
@@ -709,7 +712,12 @@  convert_modes (enum machine_mode mode, enum machine_mode oldmode, rtx x, int uns
   if (GET_CODE (x) == SUBREG && SUBREG_PROMOTED_VAR_P (x)
       && GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) >= GET_MODE_SIZE (mode)
       && SUBREG_PROMOTED_UNSIGNED_P (x) == unsignedp)
-    x = gen_lowpart (mode, x);
+    {
+      if (no_emit)
+	x = rtl_hooks.gen_lowpart_no_emit (mode, x);
+      else
+	x = gen_lowpart (mode, x);
+    }
 
   if (GET_MODE (x) != VOIDmode)
     oldmode = GET_MODE (x);
@@ -773,7 +781,10 @@  convert_modes (enum machine_mode mode, enum machine_mode oldmode, rtx x, int uns
 	  return gen_int_mode (val, mode);
 	}
 
-      return gen_lowpart (mode, x);
+      if (no_emit)
+	return rtl_hooks.gen_lowpart_no_emit (mode, x);
+      else
+	return gen_lowpart (mode, x);
     }
 
   /* Converting from integer constant into mode is always equivalent to an
@@ -784,10 +795,20 @@  convert_modes (enum machine_mode mode, enum machine_mode oldmode, rtx x, int uns
       return simplify_gen_subreg (mode, x, oldmode, 0);
     }
 
+  if (no_emit)
+    return NULL_RTX;
+
   temp = gen_reg_rtx (mode);
   convert_move (temp, x, unsignedp);
   return temp;
 }
+
+rtx
+convert_modes (enum machine_mode mode, enum machine_mode oldmode,
+	       rtx x, int unsignedp)
+{
+  return convert_modes_1 (mode, oldmode, x, unsignedp, false);
+}
 
 /* Return the largest alignment we can use for doing a move (or store)
    of MAX_PIECES.  ALIGN is the largest alignment we could use.  */
diff --git a/gcc/expr.h b/gcc/expr.h
index cb4050d..2ac9788 100644
--- a/gcc/expr.h
+++ b/gcc/expr.h
@@ -267,6 +267,8 @@  extern rtx convert_to_mode (enum machine_mode, rtx, int);
 
 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 extern rtx convert_modes (enum machine_mode, enum machine_mode, rtx, int);
+extern rtx convert_modes_1 (enum machine_mode, enum machine_mode, rtx,
+			    int, bool);
 
 /* Emit code to move a block Y to a block X.  */
 
diff --git a/gcc/rtl.h b/gcc/rtl.h
index e3ceecd..1497d50 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -1638,8 +1638,14 @@  extern int byte_lowpart_offset (enum machine_mode, enum machine_mode);
 extern rtx make_safe_from (rtx, rtx);
 extern rtx convert_memory_address_addr_space (enum machine_mode, rtx,
 					      addr_space_t);
+extern rtx convert_memory_address_addr_space_1 (enum machine_mode, rtx,
+						addr_space_t, bool, bool);
 #define convert_memory_address(to_mode,x) \
 	convert_memory_address_addr_space ((to_mode), (x), ADDR_SPACE_GENERIC)
+#define convert_memory_address_1(to_mode,x,no_emit,ignore_address_wrap_around) \
+	convert_memory_address_addr_space_1 ((to_mode), (x), \
+					     ADDR_SPACE_GENERIC, (no_emit), \
+					     (ignore_address_wrap_around))
 extern const char *get_insn_name (int);
 extern rtx get_last_insn_anywhere (void);
 extern rtx get_first_nonnote_insn (void);
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 82b818b..c62aab1 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -1150,7 +1150,7 @@  simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
 		  && REG_P (SUBREG_REG (op))
 		  && REG_POINTER (SUBREG_REG (op))
 		  && GET_MODE (SUBREG_REG (op)) == Pmode)))
-	return convert_memory_address (Pmode, op);
+	return convert_memory_address_1 (Pmode, op, true, false);
 #endif
       break;
 
@@ -1243,7 +1243,7 @@  simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
 		  && REG_P (SUBREG_REG (op))
 		  && REG_POINTER (SUBREG_REG (op))
 		  && GET_MODE (SUBREG_REG (op)) == Pmode)))
-	return convert_memory_address (Pmode, op);
+	return convert_memory_address_1 (Pmode, op, true, false);
 #endif
       break;