[PATCH]middle-end: Don't ICE during gimple_build of an incomplete PHI node

[Tamar Christina]

The new building APIs e.g. gimple_build APIs at the moment ICE if you try to
build a PHI node without all the arguments set yet.  However this workflow is
quite common, especially in the vectorizer.

This change allows this case by just not folding the PHI is any argument is
missing as we don't know the value, we also don't know if it's nonnegative.

Bootstrapped Regtested on aarch64-none-linux-gnu,
arm-none-linux-gnueabihf, x86_64-pc-linux-gnu
-m32, -m64 and no issues

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

        * gimple-fold.cc (gimple_phi_nonnegative_warnv_p): If the arguments
        aren't defined, then return false.

---
diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index 
edcc04adc08cf15cff36d436caa31c0cfbff8f9a..bed760b9c0d538e2f874f5a1263a0d2db5486a86
 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -11386,7 +11386,9 @@ gimple_phi_nonnegative_warnv_p (gimple *stmt, bool 
*strict_overflow_p,
   for (unsigned i = 0; i < gimple_phi_num_args (stmt); ++i)
     {
       tree arg = gimple_phi_arg_def (stmt, i);
-      if (!tree_single_nonnegative_warnv_p (arg, strict_overflow_p, depth + 1))
+      if (!arg
+         || !tree_single_nonnegative_warnv_p (arg, strict_overflow_p,
+                                              depth + 1))
        return false;
     }
   return true;


-- 

diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index edcc04adc08cf15cff36d436caa31c0cfbff8f9a..bed760b9c0d538e2f874f5a1263a0d2db5486a86 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -11386,7 +11386,9 @@ gimple_phi_nonnegative_warnv_p (gimple *stmt, bool *strict_overflow_p,
   for (unsigned i = 0; i < gimple_phi_num_args (stmt); ++i)
     {
       tree arg = gimple_phi_arg_def (stmt, i);
-      if (!tree_single_nonnegative_warnv_p (arg, strict_overflow_p, depth + 1))
+      if (!arg
+	  || !tree_single_nonnegative_warnv_p (arg, strict_overflow_p,
+					       depth + 1))
 	return false;
     }
   return true;