From patchwork Wed Aug  4 16:30:30 2010
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Subject: Combiner fixes
Date: Wed, 04 Aug 2010 06:30:30 -0000
From: Bernd Schmidt <bernds@codesourcery.com>
X-Patchwork-Id: 60871
Message-Id: <4C5995A6.8050701@codesourcery.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Paolo Bonzini <bonzini@gnu.org>, GCC Patches <gcc-patches@gcc.gnu.org>,
 Richard Earnshaw <rearnsha@arm.com>

On 08/04/2010 05:39 PM, H.J. Lu wrote:
> This caused:
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45182

This seems to be a latent bug.  We call make_compound_operation on

(plus:V2DI (ashift:V2DI (reg:V2DI 137)
        (const_int 2 [0x2]))
    (reg:V2DI 145))

and try to convert the shift into a multiplication, and
trunc_int_for_mode fails when asked to do something with V2DImode.

I think it's best not to do any of that for anything but plain integer
modes.  Ok if tests pass?


Bernd
PR middle-end/45182
	* combine.c (make_compound_operation): Don't try to convert
	shifts into multiplications for modes that aren't SCALAR_INT_MODE_P.

	PR middle-end/45182
	* gcc.c-torture/compile/pr45182.c: New test.


Index: combine.c
===================================================================
--- combine.c	(revision 162849)
+++ combine.c	(working copy)
@@ -7093,7 +7093,9 @@ make_compound_operation (rtx x, enum rtx
      address, we stay there.  If we have a comparison, set to COMPARE,
      but once inside, go back to our default of SET.  */
 
-  next_code = (code == MEM || code == PLUS || code == MINUS ? MEM
+  next_code = (code == MEM ? MEM
+	       : ((code == PLUS || code == MINUS)
+		  && SCALAR_INT_MODE_P (mode)) ? MEM
 	       : ((code == COMPARE || COMPARISON_P (x))
 		  && XEXP (x, 1) == const0_rtx) ? COMPARE
 	       : in_code == COMPARE ? SET : in_code);
@@ -7127,8 +7129,8 @@ make_compound_operation (rtx x, enum rtx
     case PLUS:
       lhs = XEXP (x, 0);
       rhs = XEXP (x, 1);
-      lhs = make_compound_operation (lhs, MEM);
-      rhs = make_compound_operation (rhs, MEM);
+      lhs = make_compound_operation (lhs, next_code);
+      rhs = make_compound_operation (rhs, next_code);
       if (GET_CODE (lhs) == MULT && GET_CODE (XEXP (lhs, 0)) == NEG
 	  && SCALAR_INT_MODE_P (mode))
 	{
@@ -7157,8 +7159,8 @@ make_compound_operation (rtx x, enum rtx
     case MINUS:
       lhs = XEXP (x, 0);
       rhs = XEXP (x, 1);
-      lhs = make_compound_operation (lhs, MEM);
-      rhs = make_compound_operation (rhs, MEM);
+      lhs = make_compound_operation (lhs, next_code);
+      rhs = make_compound_operation (rhs, next_code);
       if (GET_CODE (rhs) == MULT && GET_CODE (XEXP (rhs, 0)) == NEG
 	  && SCALAR_INT_MODE_P (mode))
 	{
Index: testsuite/gcc.c-torture/compile/pr45182.c
===================================================================
--- testsuite/gcc.c-torture/compile/pr45182.c	(revision 0)
+++ testsuite/gcc.c-torture/compile/pr45182.c	(revision 0)
@@ -0,0 +1,10 @@
+typedef struct TypHeader {
+  struct TypHeader ** ptr;
+} *TypHandle;
+void PlainRange (TypHandle hdList, long lenList, long low, long inc)
+{
+  long i;
+  for (i = 1; i <= lenList; i++ )
+    (((TypHandle*)((hdList)->ptr))[i] = (((TypHandle) (((long)(low + (i-1) *
+inc) << 2) + 1))));
+}