[PATCH, i386]: Fix PR50202, ICE: in final_scan_insn, at final.c:2709 (could not split insn) with __builtin_ia32_pcmpistri128

[Uros Bizjak]

Hello!

Attached patch fixes corner case with -fno-dse, where the insn has all
outputs unused. Do not bother with the insn in this case and simply
delete it from splitter.

2011-08-27  Uros Bizjak  <ubiz...@gmail.com>

        PR target/50202
        * config/i386/sse.md (sse4_2_pcmpestr): Emit NOTE_INSN_DELETED note
        when all outputs are unused.
        (sse4_2_pcmpistr): Ditto.

testsuite/ChangeLog:

2011-08-27  Uros Bizjak  <ubiz...@gmail.com>

        PR target/50202
        * gcc.target/i386/pr50202.c: New test.

Bootstrapped and regression tested on x86_64-pc-linux-gnu  {,-m32}.
Committed to mainline SVN and to 4.6.

Uros.

Index: config/i386/sse.md
===================================================================
--- config/i386/sse.md  (revision 178129)
+++ config/i386/sse.md  (working copy)
@@ -9734,6 +9734,9 @@
                                           operands[2], operands[3],
                                           operands[4], operands[5],
                                           operands[6]));
+  if (!(flags || ecx || xmm0))
+    emit_note (NOTE_INSN_DELETED);
+
   DONE;
 }
   [(set_attr "type" "sselog")
@@ -9861,6 +9864,9 @@
     emit_insn (gen_sse4_2_pcmpistr_cconly (NULL, NULL,
                                           operands[2], operands[3],
                                           operands[4]));
+  if (!(flags || ecx || xmm0))
+    emit_note (NOTE_INSN_DELETED);
+
   DONE;
 }
   [(set_attr "type" "sselog")
Index: testsuite/gcc.target/i386/pr50202.c
===================================================================
--- testsuite/gcc.target/i386/pr50202.c (revision 0)
+++ testsuite/gcc.target/i386/pr50202.c (revision 0)
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fno-tree-dse -fno-dce -msse4" } */
+/* { dg-require-effective-target sse4 } */
+
+typedef char __v16qi __attribute__ ((__vector_size__ (16)));
+
+__v16qi v;
+int i;
+
+void
+foo (void)
+{
+  i = __builtin_ia32_pcmpistri128 (v, v, 255);
+  i = 255;
+}