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* [PATCH] Fix PR69047
@ 2016-08-26 12:31 Richard Biener
  2016-08-29  9:22 ` Andreas Schwab
  0 siblings, 1 reply; 3+ messages in thread
From: Richard Biener @ 2016-08-26 12:31 UTC (permalink / raw)
  To: gcc-patches


The following fixes PR69047, update-address-taken can use the same
trick as VN and re-write MEM[&d] into SSA when the size of the MEM
and the size of d do not match by using a BIT_FIELD_REF.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

The patch contains a workaround for PR77390.

Richard.

2016-08-26  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/69047
	* tree-ssa.c (maybe_rewrite_mem_ref_base): Handle general bitfield
	extracts similar to what FRE does.
	(non_rewritable_mem_ref_base): Likewise.

	* gcc.dg/pr69047.c: New testcase.

Index: gcc/tree-ssa.c
===================================================================
--- gcc/tree-ssa.c	(revision 239752)
+++ gcc/tree-ssa.c	(working copy)
@@ -1292,7 +1292,9 @@ maybe_rewrite_mem_ref_base (tree *tp, bi
       && (sym = TREE_OPERAND (TREE_OPERAND (*tp, 0), 0))
       && DECL_P (sym)
       && !TREE_ADDRESSABLE (sym)
-      && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym)))
+      && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym))
+      && is_gimple_reg_type (TREE_TYPE (*tp))
+      && ! VOID_TYPE_P (TREE_TYPE (*tp)))
     {
       if (TREE_CODE (TREE_TYPE (sym)) == VECTOR_TYPE
 	  && useless_type_conversion_p (TREE_TYPE (*tp),
@@ -1314,7 +1316,8 @@ maybe_rewrite_mem_ref_base (tree *tp, bi
 			? REALPART_EXPR : IMAGPART_EXPR,
 			TREE_TYPE (*tp), sym);
 	}
-      else if (integer_zerop (TREE_OPERAND (*tp, 1)))
+      else if (integer_zerop (TREE_OPERAND (*tp, 1))
+	       && DECL_SIZE (sym) == TYPE_SIZE (TREE_TYPE (*tp)))
 	{
 	  if (!useless_type_conversion_p (TREE_TYPE (*tp),
 					  TREE_TYPE (sym)))
@@ -1323,6 +1326,24 @@ maybe_rewrite_mem_ref_base (tree *tp, bi
 	  else
 	    *tp = sym;
 	}
+      else if (DECL_SIZE (sym)
+	       && TREE_CODE (DECL_SIZE (sym)) == INTEGER_CST
+	       && mem_ref_offset (*tp) >= 0
+	       && wi::leu_p (mem_ref_offset (*tp)
+			     + wi::to_offset (TYPE_SIZE_UNIT (TREE_TYPE (*tp))),
+			     wi::to_offset (DECL_SIZE_UNIT (sym)))
+	       && (! INTEGRAL_TYPE_P (TREE_TYPE (*tp)) 
+		   || (wi::to_offset (TYPE_SIZE (TREE_TYPE (*tp)))
+		       == TYPE_PRECISION (TREE_TYPE (*tp))))
+	       && wi::umod_trunc (wi::to_offset (TYPE_SIZE (TREE_TYPE (*tp))),
+				  BITS_PER_UNIT) == 0)
+	{
+	  *tp = build3 (BIT_FIELD_REF, TREE_TYPE (*tp), sym,
+			TYPE_SIZE (TREE_TYPE (*tp)),
+			wide_int_to_tree (bitsizetype,
+					  mem_ref_offset (*tp)
+					  << LOG2_BITS_PER_UNIT));
+	}
     }
 }
 
@@ -1352,6 +1373,11 @@ non_rewritable_mem_ref_base (tree ref)
       && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR)
     {
       tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0);
+      if (! DECL_P (decl))
+	return NULL_TREE;
+      if (! is_gimple_reg_type (TREE_TYPE (base))
+	  || VOID_TYPE_P (TREE_TYPE (base)))
+	return decl;
       if ((TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE
 	   || TREE_CODE (TREE_TYPE (decl)) == COMPLEX_TYPE)
 	  && useless_type_conversion_p (TREE_TYPE (base),
@@ -1362,12 +1388,28 @@ non_rewritable_mem_ref_base (tree ref)
 	  && multiple_of_p (sizetype, TREE_OPERAND (base, 1),
 			    TYPE_SIZE_UNIT (TREE_TYPE (base))))
 	return NULL_TREE;
-      if (DECL_P (decl)
-	  && (!integer_zerop (TREE_OPERAND (base, 1))
-	      || (DECL_SIZE (decl)
-		  != TYPE_SIZE (TREE_TYPE (base)))
-	      || TREE_THIS_VOLATILE (decl) != TREE_THIS_VOLATILE (base)))
-	return decl;
+      /* For same sizes and zero offset we can use a VIEW_CONVERT_EXPR.  */
+      if (integer_zerop (TREE_OPERAND (base, 1))
+	  && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (base)))
+	return NULL_TREE;
+      /* For integral typed extracts we can use a BIT_FIELD_REF.  */
+      if (DECL_SIZE (decl)
+	  && TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST
+	  && mem_ref_offset (base) >= 0
+	  && wi::leu_p (mem_ref_offset (base)
+			+ wi::to_offset (TYPE_SIZE_UNIT (TREE_TYPE (base))),
+			wi::to_offset (DECL_SIZE_UNIT (decl)))
+	  /* ???  We can't handle bitfield precision extracts without
+	     either using an alternate type for the BIT_FIELD_REF and
+	     then doing a conversion or possibly adjusting the offset
+	     according to endianess.  */
+	  && (! INTEGRAL_TYPE_P (TREE_TYPE (base))
+	      || (wi::to_offset (TYPE_SIZE (TREE_TYPE (base)))
+		  == TYPE_PRECISION (TREE_TYPE (base))))
+	  && wi::umod_trunc (wi::to_offset (TYPE_SIZE (TREE_TYPE (base))),
+			     BITS_PER_UNIT) == 0)
+	return NULL_TREE;
+      return decl;
     }
 
   return NULL_TREE;
Index: gcc/testsuite/gcc.dg/pr69047.c
===================================================================
--- gcc/testsuite/gcc.dg/pr69047.c	(revision 0)
+++ gcc/testsuite/gcc.dg/pr69047.c	(working copy)
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-cddce1" } */
+
+__UINT8_TYPE__
+f(__UINT16_TYPE__ b)
+{
+  __UINT8_TYPE__ a;
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+  __builtin_memcpy(&a, &b, sizeof a);
+#elif __BYTE_ORDER == __BIG_ENDIAN
+  __builtin_memcpy(&a, (char *)&b + sizeof a, sizeof a);
+#else
+  a = b;
+#endif
+  return a;
+}
+
+/* { dg-final { scan-tree-dump "_\[0-9\]+ = \\(\[^)\]+\\) b" "cddce1" } } */

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] Fix PR69047
  2016-08-26 12:31 [PATCH] Fix PR69047 Richard Biener
@ 2016-08-29  9:22 ` Andreas Schwab
  2016-08-30  9:22   ` Richard Biener
  0 siblings, 1 reply; 3+ messages in thread
From: Andreas Schwab @ 2016-08-29  9:22 UTC (permalink / raw)
  To: Richard Biener; +Cc: gcc-patches

On Aug 26 2016, Richard Biener <rguenther@suse.de> wrote:

> Index: gcc/testsuite/gcc.dg/pr69047.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/pr69047.c	(revision 0)
> +++ gcc/testsuite/gcc.dg/pr69047.c	(working copy)
> @@ -0,0 +1,18 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-tree-cddce1" } */
> +
> +__UINT8_TYPE__
> +f(__UINT16_TYPE__ b)
> +{
> +  __UINT8_TYPE__ a;
> +#if __BYTE_ORDER == __LITTLE_ENDIAN
> +  __builtin_memcpy(&a, &b, sizeof a);
> +#elif __BYTE_ORDER == __BIG_ENDIAN
> +  __builtin_memcpy(&a, (char *)&b + sizeof a, sizeof a);
> +#else
> +  a = b;
> +#endif
> +  return a;
> +}
> +
> +/* { dg-final { scan-tree-dump "_\[0-9\]+ = \\(\[^)\]+\\) b" "cddce1" } } */
>

On m68k:

FAIL: gcc.dg/pr69047.c scan-tree-dump cddce1 "_[0-9]+ = \\([^)]+\\) b"

$ cat pr69047.c.037t.cddce1 

;; Function f (f, funcdef_no=0, decl_uid=1432, cgraph_uid=0, symbol_order=0)

f (short unsigned int b)
{
  unsigned char a;
  unsigned char _2;

  <bb 2>:
  _2 = BIT_FIELD_REF <b_6(D), 8, 0>;
  return _2;

}


Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] Fix PR69047
  2016-08-29  9:22 ` Andreas Schwab
@ 2016-08-30  9:22   ` Richard Biener
  0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2016-08-30  9:22 UTC (permalink / raw)
  To: Andreas Schwab; +Cc: gcc-patches

On Mon, 29 Aug 2016, Andreas Schwab wrote:

> On Aug 26 2016, Richard Biener <rguenther@suse.de> wrote:
> 
> > Index: gcc/testsuite/gcc.dg/pr69047.c
> > ===================================================================
> > --- gcc/testsuite/gcc.dg/pr69047.c	(revision 0)
> > +++ gcc/testsuite/gcc.dg/pr69047.c	(working copy)
> > @@ -0,0 +1,18 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O -fdump-tree-cddce1" } */
> > +
> > +__UINT8_TYPE__
> > +f(__UINT16_TYPE__ b)
> > +{
> > +  __UINT8_TYPE__ a;
> > +#if __BYTE_ORDER == __LITTLE_ENDIAN
> > +  __builtin_memcpy(&a, &b, sizeof a);
> > +#elif __BYTE_ORDER == __BIG_ENDIAN
> > +  __builtin_memcpy(&a, (char *)&b + sizeof a, sizeof a);
> > +#else
> > +  a = b;
> > +#endif
> > +  return a;
> > +}
> > +
> > +/* { dg-final { scan-tree-dump "_\[0-9\]+ = \\(\[^)\]+\\) b" "cddce1" } } */
> >
> 
> On m68k:
> 
> FAIL: gcc.dg/pr69047.c scan-tree-dump cddce1 "_[0-9]+ = \\([^)]+\\) b"
> 
> $ cat pr69047.c.037t.cddce1 
> 
> ;; Function f (f, funcdef_no=0, decl_uid=1432, cgraph_uid=0, symbol_order=0)
> 
> f (short unsigned int b)
> {
>   unsigned char a;
>   unsigned char _2;
> 
>   <bb 2>:
>   _2 = BIT_FIELD_REF <b_6(D), 8, 0>;
>   return _2;
> 
> }
> 
> 
> Andreas.

Ah, forgot to re-write to use GCC internal macros.

Tested on m68k, applied.

Richard.

2016-08-30  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/69047
	* gcc.dg/pr69047.c: Fix byte-order check.

Index: gcc/testsuite/gcc.dg/pr69047.c
===================================================================
--- gcc/testsuite/gcc.dg/pr69047.c	(revision 239856)
+++ gcc/testsuite/gcc.dg/pr69047.c	(working copy)
@@ -5,9 +5,9 @@ __UINT8_TYPE__
 f(__UINT16_TYPE__ b)
 {
   __UINT8_TYPE__ a;
-#if __BYTE_ORDER == __LITTLE_ENDIAN
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
   __builtin_memcpy(&a, &b, sizeof a);
-#elif __BYTE_ORDER == __BIG_ENDIAN
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
   __builtin_memcpy(&a, (char *)&b + sizeof a, sizeof a);
 #else
   a = b;

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2016-08-26 12:31 [PATCH] Fix PR69047 Richard Biener
2016-08-29  9:22 ` Andreas Schwab
2016-08-30  9:22   ` Richard Biener

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