[PATCH] Fix ICE with V1DImode ctor (PR middle-end/71626, take 2)

[Jakub Jelinek <jakub at redhat dot com>]

On Tue, Jun 28, 2016 at 09:15:13AM +0200, Richard Biener wrote:
> I wonder why we can rely on the MODE_FLOAT case not seeing
> (subreg:DF (reg:V2DF ) 0) but have to handle
> (subreg:V1DF (reg:DF ...) 0) in the MODE_VECTOR case.

Seems all of force_const_mem is just unprepared to handle SUBREGs
of CONSTANT_P, IMNSHO the bug is that callers shouldn't be trying
to do that.

So, this patch instead changes ix86_expand_vector_move, so that
for SUBREGs it forces the SUBREG_REG into memory (or register if
that fails, though I don't have a testcase for when that would happen),
and just re-creates a SUBREG on the forced MEM (for whole size
SUBREGs that is in the end just using different mode for the MEM).

Ok for trunk if it passes bootstrap/regtest?
I have tried the PR32065 testcase, but we don't end up with SUBREG
in that case, since we have CONST_WIDE_INT support in ix86 backend.

The relocation issue is solved by this automatically, the constant pool
code without the unexpected SUBREG around it figures for -fpic out that
there are relocations needed and uses .data.rel.ro section instead of
.rodata.*.

2016-06-28  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/71626
	* config/i386/i386.c (ix86_expand_vector_move): For SUBREG of
	a constant, force its SUBREG_REG into memory or register instead
	of whole op1.

	* gcc.c-torture/execute/pr71626-1.c: New test.
	* gcc.c-torture/execute/pr71626-2.c: New test.

--- gcc/config/i386/i386.c.jj	2016-06-27 14:50:51.000000000 +0200
+++ gcc/config/i386/i386.c	2016-06-28 10:51:18.444624190 +0200
@@ -19610,12 +19610,29 @@ ix86_expand_vector_move (machine_mode mo
      of the register, once we have that information we may be able
      to handle some of them more efficiently.  */
   if (can_create_pseudo_p ()
-      && register_operand (op0, mode)
       && (CONSTANT_P (op1)
 	  || (SUBREG_P (op1)
 	      && CONSTANT_P (SUBREG_REG (op1))))
-      && !standard_sse_constant_p (op1, mode))
-    op1 = validize_mem (force_const_mem (mode, op1));
+      && ((register_operand (op0, mode)
+	   && !standard_sse_constant_p (op1, mode))
+	  /* ix86_expand_vector_move_misalign() does not like constants.  */
+	  || (SSE_REG_MODE_P (mode)
+	      && MEM_P (op0)
+	      && MEM_ALIGN (op0) < align)))
+    {
+      if (SUBREG_P (op1))
+	{
+	  machine_mode imode = GET_MODE (SUBREG_REG (op1));
+	  rtx r = force_const_mem (imode, SUBREG_REG (op1));
+	  if (r)
+	    r = validize_mem (r);
+	  else
+	    r = force_reg (imode, SUBREG_REG (op1));
+	  op1 = simplify_gen_subreg (mode, r, imode, SUBREG_BYTE (op1));
+	}
+      else
+	op1 = validize_mem (force_const_mem (mode, op1));
+    }
 
   /* We need to check memory alignment for SSE mode since attribute
      can make operands unaligned.  */
@@ -19626,13 +19643,8 @@ ix86_expand_vector_move (machine_mode mo
     {
       rtx tmp[2];
 
-      /* ix86_expand_vector_move_misalign() does not like constants ... */
-      if (CONSTANT_P (op1)
-	  || (SUBREG_P (op1)
-	      && CONSTANT_P (SUBREG_REG (op1))))
-	op1 = validize_mem (force_const_mem (mode, op1));
-
-      /* ... nor both arguments in memory.  */
+      /* ix86_expand_vector_move_misalign() does not like both
+	 arguments in memory.  */
       if (!register_operand (op0, mode)
 	  && !register_operand (op1, mode))
 	op1 = force_reg (mode, op1);
--- gcc/testsuite/gcc.c-torture/execute/pr71626-1.c.jj	2016-06-28 10:40:12.928186649 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr71626-1.c	2016-06-28 10:40:12.928186649 +0200
@@ -0,0 +1,19 @@
+/* PR middle-end/71626 */
+
+typedef __INTPTR_TYPE__ V __attribute__((__vector_size__(sizeof (__INTPTR_TYPE__))));
+
+__attribute__((noinline, noclone)) V
+foo ()
+{
+  V v = { (__INTPTR_TYPE__) foo };
+  return v;
+}
+
+int
+main ()
+{
+  V v = foo ();
+  if (v[0] != (__INTPTR_TYPE__) foo)
+    __builtin_abort ();
+  return 0;
+}
--- gcc/testsuite/gcc.c-torture/execute/pr71626-2.c.jj	2016-06-28 10:40:12.928186649 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr71626-2.c	2016-06-28 10:40:12.928186649 +0200
@@ -0,0 +1,4 @@
+/* PR middle-end/71626 */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+#include "pr71626-1.c"


	Jakub