[patch] Fix PR tree-optimization/49318

[Ira Rosen]

Hi,

The test in PR 49318 fails because the vectorizer recognizes address
computation sequence as a widening-multiplication pattern, while such
sequence is not relevant to vectorization. The problem is that the
vectorizer doesn't check if a statement is going to be vectorized
before replacing it with a pattern. Moreover, the vectorizer first
detects the patterns and only after that looks for relevant
statements. Changing the order is not a good option, since statements
relevance is defined also by their belonging to a pattern.

This patch solves the problem by removing pattern statements that were
created for statements that are not supposed to be vectorized.

Bootstrapped with vectorization enabled on powerpc64-suse-linux and
tested on powerpc64-suse-linux and x86_64-suse-linux.
Committed.

Ira

ChangeLog:

     PR tree-optimization/49318
     * tree-vect-loop.c (vect_determine_vectorization_factor):
     Remove irrelevant pattern statements.

testsuite/ChangeLog:

     PR tree-optimization/49318
     * gcc.dg/vect/pr49318.c: New test.
-------------- next part --------------
Index: ChangeLog
===================================================================
--- ChangeLog	(revision 174889)
+++ ChangeLog	(working copy)
@@ -1,3 +1,9 @@
+2011-06-10  Ira Rosen  <ira.rosen@linaro.org>
+
+	PR tree-optimization/49318
+	* tree-vect-loop.c (vect_determine_vectorization_factor): Remove
+	irrelevant pattern statements.
+
 2011-06-10  Hans-Peter Nilsson  <hp@axis.com>
 
 	* system.h (SETJMP_VIA_SAVE_AREA): Poison.
Index: testsuite/gcc.dg/vect/pr49318.c
===================================================================
--- testsuite/gcc.dg/vect/pr49318.c	(revision 0)
+++ testsuite/gcc.dg/vect/pr49318.c	(revision 0)
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-require-effective-target vect_float } */
+
+typedef enum { GL_FALSE } GLenum;
+typedef unsigned char GLboolean;
+typedef int GLint;
+typedef unsigned int GLuint;
+typedef float GLfloat;
+typedef double GLdouble;
+typedef struct gl_context GLcontext;
+struct gl_context {
+  GLfloat TextureMatrix[16];
+  GLenum Primitive;
+};
+void gl_GetDoublev( GLcontext *ctx, GLenum pname, GLdouble *params ) {
+  GLuint i;
+  for (i=0; i<16; i++)
+    params[i] = (GLint) ctx->TextureMatrix[i];
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */
Index: testsuite/ChangeLog
===================================================================
--- testsuite/ChangeLog	(revision 174889)
+++ testsuite/ChangeLog	(working copy)
@@ -1,3 +1,8 @@
+2011-06-10  Ira Rosen  <ira.rosen@linaro.org>
+
+	PR tree-optimization/49318
+	* gcc.dg/vect/pr49318.c: New test.
+
 2011-06-09  David Krauss  <potswa@mac.com>
 
 	* g++.dg/template/arrow1.C: New.
Index: tree-vect-loop.c
===================================================================
--- tree-vect-loop.c	(revision 174889)
+++ tree-vect-loop.c	(working copy)
@@ -255,10 +255,20 @@ vect_determine_vectorization_factor (loop_vec_info
 
 	  gcc_assert (stmt_info);
 
-	  /* skip stmts which do not need to be vectorized.  */
+	  /* Skip stmts which do not need to be vectorized.  */
 	  if (!STMT_VINFO_RELEVANT_P (stmt_info)
 	      && !STMT_VINFO_LIVE_P (stmt_info))
 	    {
+              if (is_pattern_stmt_p (stmt_info))
+                {
+                   /* We are not going to vectorize this pattern statement,
+                      therefore, remove it.  */
+                  gimple_stmt_iterator tmp_gsi = gsi_for_stmt (stmt);
+                  STMT_VINFO_RELATED_STMT (stmt_info) = NULL;
+                  gsi_remove (&tmp_gsi, true);
+                  free_stmt_vec_info (stmt);
+                }
+
 	      if (vect_print_dump_info (REPORT_DETAILS))
 	        fprintf (vect_dump, "skip.");
 	      continue;