From: Marek Polacek <polacek@redhat.com>
Date: Fri, 22 Apr 2022 23:40:27 +0000 (-0400)
Subject: c++: __builtin_shufflevector with value-dep expr [PR105353]
X-Git-Tag: basepoints/gcc-13~65
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1ba397e9f93d3abc93a6ecbabc3d873489a6fb7f;p=thirdparty%2Fgcc.git

c++: __builtin_shufflevector with value-dep expr [PR105353]

Here we issue an error from c_build_shufflevector while parsing a template
because it got a TEMPLATE_PARM_INDEX, but this function expects INTEGER_CSTs
(except the first two arguments).  It checks if any of the arguments are
type-dependent, if so, we leave the processing for later, but it should
also check value-dependency for the 3rd+ arguments, so as to avoid the
problem above.

This is not a regression -- __builtin_shufflevector was introduced in
GCC 12, but it looks safe enough.

	PR c++/105353

gcc/cp/ChangeLog:

	* typeck.cc (build_x_shufflevector): Use
	instantiation_dependent_expression_p except for the first two
	arguments.

gcc/testsuite/ChangeLog:

	* g++.dg/ext/builtin-shufflevector-3.C: New test.
---

diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 26a7cb4b50d5..0da6f2485d02 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -6315,7 +6315,9 @@ build_x_shufflevector (location_t loc, vec<tree, va_gc> *args,
   if (processing_template_decl)
     {
       for (unsigned i = 0; i < args->length (); ++i)
-	if (type_dependent_expression_p ((*args)[i]))
+	if (i <= 1
+	    ? type_dependent_expression_p ((*args)[i])
+	    : instantiation_dependent_expression_p ((*args)[i]))
 	  {
 	    tree exp = build_min_nt_call_vec (NULL, args);
 	    CALL_EXPR_IFN (exp) = IFN_SHUFFLEVECTOR;
diff --git a/gcc/testsuite/g++.dg/ext/builtin-shufflevector-3.C b/gcc/testsuite/g++.dg/ext/builtin-shufflevector-3.C
new file mode 100644
index 000000000000..0f3cbbee563a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/builtin-shufflevector-3.C
@@ -0,0 +1,23 @@
+// PR c++/105353
+// { dg-do compile { target c++17 } }
+// { dg-additional-options "-Wno-psabi" }
+
+typedef unsigned char Simd128U8VectT __attribute__((__vector_size__(16)));
+
+template<int ShuffleIndex>
+static inline Simd128U8VectT ShufFunc(Simd128U8VectT vect) noexcept {
+    if constexpr(unsigned(ShuffleIndex) >= 16)
+        return Simd128U8VectT { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+    else if constexpr(ShuffleIndex == 0)
+        return vect;
+    else
+        return __builtin_shufflevector(vect, vect, ShuffleIndex, ShuffleIndex + 1,
+            ShuffleIndex + 2, ShuffleIndex + 3, ShuffleIndex + 4, ShuffleIndex + 5,
+            ShuffleIndex + 6, ShuffleIndex + 7, ShuffleIndex + 8, ShuffleIndex + 9,
+            ShuffleIndex + 10, ShuffleIndex + 11, ShuffleIndex + 12, ShuffleIndex + 13,
+            ShuffleIndex + 14, ShuffleIndex + 15);
+}
+
+auto func1(Simd128U8VectT vect) noexcept {
+    return ShufFunc<5>(vect);
+}