Add an error when calling a builtin that requires features that don't

match the feature set of the function that they're being called from.

This ensures that we can effectively diagnose some[1] code that would
instead ICE in the backend with a failure to select message.

Example:

__m128d foo(__m128d a, __m128d b) {
  return __builtin_ia32_addsubps(b, a);
}

compiled for normal x86_64 via:

clang -target x86_64-linux-gnu -c

would fail to compile in the back end because the normal subtarget
features for x86_64 only include sse2 and the builtin requires sse3.

[1] We're still not erroring on:

__m128i bar(__m128i const *p) { return _mm_lddqu_si128(p); }

where we should fail and error on an always_inline function being
inlined into a function that doesn't support the subtarget features
required.

llvm-svn: 250473

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/test/CodeGen/target-builtin-error-2.c b/clang/test/CodeGen/target-builtin-error-2.c
new file mode 100644
index 00000000000..949f2cc7846
--- /dev/null
+++ b/clang/test/CodeGen/target-builtin-error-2.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 %s -triple=x86_64-linux-gnu -S -verify -o -
+#define __MM_MALLOC_H
+
+#include <x86intrin.h>
+
+// Since we do code generation on a function level this needs to error out since
+// the subtarget feature won't be available.
+__m256d wombat(__m128i a) {
+  if (__builtin_cpu_supports("avx"))
+    return __builtin_ia32_cvtdq2pd256((__v4si)a); // expected-error {{'__builtin_ia32_cvtdq2pd256' needs target feature avx}}
+  else
+    return (__m256d){0, 0, 0, 0};
+}