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Re: PATCH: PR target/39162: Gcc doesn't warn __m256 when -mavx isn't used


On Thu, Feb 12, 2009 at 01:57:10PM -0800, H.J. Lu wrote:
> 
> When 256bit vector is used with AVX disabled, there is no ABI change
> warning.  Since the middle-end can't handle 256bit vector without AVX,
> this patch just warns the ABI change without changing BLKmode to
> vector mode.  OK for trunk?
> 

Here is the updated patch. It warns ABI changes only if AVX isn't
enabled. OK for trunk if there are no regressions?

Thanks.


H.J.
---
gcc/

2009-02-12  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/39162
	* config/i386/i386.c (type_natural_mode): Add a new argument.
	Return the original mode and warn ABI change if vector size
	is 32byte.
	(function_arg_advance): Updated.
	(function_arg): Likewise.
	(ix86_function_value): Likewise.
	(ix86_return_in_memory): Likewise.
	(ix86_sol10_return_in_memory): Likewise.
	(ix86_gimplify_va_arg): Likewise.
	(function_arg_32): Don't warn ABX ABI change here.
	(function_arg_64): Likewise.

gcc/testsuite/

2009-02-12  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/39162
	* gcc.target/i386/pr39162.c: New.

Index: gcc/testsuite/gcc.target/i386/pr39162.c
===================================================================
--- gcc/testsuite/gcc.target/i386/pr39162.c	(revision 0)
+++ gcc/testsuite/gcc.target/i386/pr39162.c	(revision 0)
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse2" } */
+
+typedef long long __m256i __attribute__ ((__vector_size__ (32), __may_alias__));
+
+__m256i
+bar (__m256i x) /* { dg-warning "AVX" "" } */
+{
+  return x;
+}
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c	(revision 144133)
+++ gcc/config/i386/i386.c	(working copy)
@@ -4719,17 +4719,21 @@ init_cumulative_args (CUMULATIVE_ARGS *c
    modes, the generic vector support in gcc will choose some non-vector mode
    in order to implement the type.  By computing the natural mode, we'll
    select the proper ABI location for the operand and not depend on whatever
-   the middle-end decides to do with these vector types.  */
+   the middle-end decides to do with these vector types.
+
+   The midde-end can't deal with the vector types > 16 bytes.  In this
+   case, we return the original mode and warn ABI change if CUM isn't
+   NULL.  */
 
 static enum machine_mode
-type_natural_mode (const_tree type)
+type_natural_mode (const_tree type, CUMULATIVE_ARGS *cum)
 {
   enum machine_mode mode = TYPE_MODE (type);
 
   if (TREE_CODE (type) == VECTOR_TYPE && !VECTOR_MODE_P (mode))
     {
       HOST_WIDE_INT size = int_size_in_bytes (type);
-      if ((size == 8 || size == 16)
+      if ((size == 8 || size == 16 || size == 32)
 	  /* ??? Generic code allows us to create width 1 vectors.  Ignore.  */
 	  && TYPE_VECTOR_SUBPARTS (type) > 1)
 	{
@@ -4744,7 +4748,24 @@ type_natural_mode (const_tree type)
 	  for (; mode != VOIDmode; mode = GET_MODE_WIDER_MODE (mode))
 	    if (GET_MODE_NUNITS (mode) == TYPE_VECTOR_SUBPARTS (type)
 		&& GET_MODE_INNER (mode) == innermode)
-	      return mode;
+	      {
+		if (size == 32 && !TARGET_AVX)
+		  {
+		    static bool warnedavx;
+
+		    if (cum
+			&& !warnedavx 
+			&& cum->warn_avx)
+		      {
+			warnedavx = true;
+			warning (0, "AVX vector argument without AVX "
+				 " enabled changes the ABI");
+		      }
+		    return TYPE_MODE (type);
+		  }
+		else
+		  return mode;
+	      }
 
 	  gcc_unreachable ();
 	}
@@ -5539,7 +5560,7 @@ function_arg_advance (CUMULATIVE_ARGS *c
   words = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
 
   if (type)
-    mode = type_natural_mode (type);
+    mode = type_natural_mode (type, NULL);
 
   if (TARGET_64BIT && (cum ? cum->call_abi : DEFAULT_ABI) == MS_ABI)
     function_arg_advance_ms_64 (cum, bytes, words);
@@ -5567,7 +5588,7 @@ function_arg_32 (CUMULATIVE_ARGS *cum, e
 		 enum machine_mode orig_mode, tree type,
 		 HOST_WIDE_INT bytes, HOST_WIDE_INT words)
 {
-  static bool warnedavx, warnedsse, warnedmmx;
+  static bool warnedsse, warnedmmx;
 
   /* Avoid the AL settings for the Unix64 ABI.  */
   if (mode == VOIDmode)
@@ -5647,12 +5668,6 @@ function_arg_32 (CUMULATIVE_ARGS *cum, e
     case V4DImode:
       if (!type || !AGGREGATE_TYPE_P (type))
 	{
-	  if (!TARGET_AVX && !warnedavx && cum->warn_avx)
-	    {
-	      warnedavx = true;
-	      warning (0, "AVX vector argument without AVX enabled "
-		       "changes the ABI");
-	    }
 	  if (cum->sse_nregs)
 	    return gen_reg_or_parallel (mode, orig_mode,
 				        cum->sse_regno + FIRST_SSE_REG);
@@ -5686,8 +5701,6 @@ static rtx
 function_arg_64 (CUMULATIVE_ARGS *cum, enum machine_mode mode,
 		 enum machine_mode orig_mode, tree type, int named)
 {
-  static bool warnedavx;
-
   /* Handle a hidden AL argument containing number of registers
      for varargs x86-64 functions.  */
   if (mode == VOIDmode)
@@ -5713,15 +5726,6 @@ function_arg_64 (CUMULATIVE_ARGS *cum, e
     case V4DImode:
       /* In 64bit, we pass TImode in interger registers and OImode on
 	 stack.  */
-      if (!type || !AGGREGATE_TYPE_P (type))
-	{
-	  if (!TARGET_AVX && !warnedavx && cum->warn_avx)
-	    {
-	      warnedavx = true;
-	      warning (0, "AVX vector argument without AVX enabled "
-		       "changes the ABI");
-	    }
-	}
 
       /* Unnamed 256bit vector mode parameters are passed on stack.  */
       if (!named)
@@ -5799,7 +5803,7 @@ function_arg (CUMULATIVE_ARGS *cum, enum
   /* To simplify the code below, represent vector types with a vector mode
      even if MMX/SSE are not active.  */
   if (type && TREE_CODE (type) == VECTOR_TYPE)
-    mode = type_natural_mode (type);
+    mode = type_natural_mode (type, cum);
 
   if (TARGET_64BIT && (cum ? cum->call_abi : DEFAULT_ABI) == MS_ABI)
     return function_arg_ms_64 (cum, mode, omode, named, bytes);
@@ -6115,7 +6119,7 @@ ix86_function_value (const_tree valtype,
   enum machine_mode mode, orig_mode;
 
   orig_mode = TYPE_MODE (valtype);
-  mode = type_natural_mode (valtype);
+  mode = type_natural_mode (valtype, NULL);
   return ix86_function_value_1 (valtype, fntype_or_decl, orig_mode, mode);
 }
 
@@ -6191,14 +6195,14 @@ ix86_return_in_memory (const_tree type, 
 #ifdef SUBTARGET_RETURN_IN_MEMORY
   return SUBTARGET_RETURN_IN_MEMORY (type, fntype);
 #else
-   const enum machine_mode mode = type_natural_mode (type);
+  const enum machine_mode mode = type_natural_mode (type, NULL);
  
   if (TARGET_64BIT_MS_ABI)
-     return return_in_memory_ms_64 (type, mode);
-   else if (TARGET_64BIT)
-     return return_in_memory_64 (type, mode);
-   else
-     return return_in_memory_32 (type, mode);
+    return return_in_memory_ms_64 (type, mode);
+  else if (TARGET_64BIT)
+    return return_in_memory_64 (type, mode);
+  else
+    return return_in_memory_32 (type, mode);
 #endif
 }
 
@@ -6211,7 +6215,7 @@ bool
 ix86_sol10_return_in_memory (const_tree type, const_tree fntype ATTRIBUTE_UNUSED)
 {
   int size;
-  enum machine_mode mode = type_natural_mode (type);
+  enum machine_mode mode = type_natural_mode (type, NULL);
 
   if (TARGET_64BIT)
     return return_in_memory_64 (type, mode);
@@ -6665,7 +6669,7 @@ ix86_gimplify_va_arg (tree valist, tree 
   size = int_size_in_bytes (type);
   rsize = (size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
 
-  nat_mode = type_natural_mode (type);
+  nat_mode = type_natural_mode (type, NULL);
   switch (nat_mode)
     {
     case V8SFmode:


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