[PATCH] Fix ICE during strstr gimple folding (PR middle-end/81207)

[Jakub Jelinek <jakub@redhat.com>]

Hi!

replace_call_with_call_and_fold has code to copy over vdef/vuse from the
old call to the new one, so that we don't have to update virtual ssa,
but it is conditioned on gimple_vdef being non-NULL and SSA_NAME.
If we have a pure function, gimple_vdef is NULL, yet we still want to copy
over the vuse.

Bootstrapped/regtested on x86_64-linux (i686-linux fails to bootstrap
with/without this patch), ok for trunk?

2017-06-27  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/81207
	* gimple-fold.c (replace_call_with_call_and_fold): Handle
	gimple_vuse copying separately from gimple_vdef copying.

	* gcc.c-torture/compile/pr81207.c: New test.

--- gcc/gimple-fold.c.jj	2017-06-19 08:28:11.000000000 +0200
+++ gcc/gimple-fold.c	2017-06-26 17:09:34.735420583 +0200
@@ -607,9 +607,11 @@ replace_call_with_call_and_fold (gimple_
       && TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
     {
       gimple_set_vdef (repl, gimple_vdef (stmt));
-      gimple_set_vuse (repl, gimple_vuse (stmt));
       SSA_NAME_DEF_STMT (gimple_vdef (repl)) = repl;
     }
+  if (gimple_vuse (stmt)
+      && TREE_CODE (gimple_vuse (stmt)) == SSA_NAME)
+    gimple_set_vuse (repl, gimple_vuse (stmt));
   gsi_replace (gsi, repl, false);
   fold_stmt (gsi);
 }
--- gcc/testsuite/gcc.c-torture/compile/pr81207.c.jj	2017-06-26 17:21:38.765918367 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr81207.c	2017-06-26 17:27:15.222966965 +0200
@@ -0,0 +1,13 @@
+/* PR middle-end/81207 */
+
+static const char *b[2] = { "'", "" };
+
+int
+foo (const char *d)
+{
+  int e;
+  for (e = 0; b[e]; e++)
+    if (__builtin_strstr (d, b[e]))
+      return 1;
+  return 0;
+}

	Jakub