Add the intrinsic __builtin_convertvector

LLVM supports applying conversion instructions to vectors of the same number of
elements (fptrunc, fptosi, etc.) but there had been no way for a Clang user to
cause such instructions to be generated when using builtin vector types.

C-style casting on vectors is already defined in terms of bitcasts, and so
cannot be used for these conversions as well (without leading to a very
confusing set of semantics). As a result, this adds a __builtin_convertvector
intrinsic (patterned after the OpenCL __builtin_astype intrinsic). This is
intended to aid the creation of vector intrinsic headers that create generic IR
instead of target-dependent intrinsics (in other words, this is a generic
_mm_cvtepi32_ps). As noted in the documentation, the action of
__builtin_convertvector is defined in terms of the action of a C-style cast on
each vector element.

llvm-svn: 190915

1 files changed, 1 insertions, 0 deletions

diff --git a/clang/test/Preprocessor/feature_tests.c b/clang/test/Preprocessor/feature_tests.c
index 19d80468ab3..5a2c300e6ee 100644
--- a/clang/test/Preprocessor/feature_tests.c
+++ b/clang/test/Preprocessor/feature_tests.c
@@ -11,6 +11,7 @@
 
 #if  !__has_builtin(__builtin_huge_val) || \
      !__has_builtin(__builtin_shufflevector) || \
+     !__has_builtin(__builtin_convertvector) || \
      !__has_builtin(__builtin_trap) || \
      !__has_builtin(__c11_atomic_init) || \
      !__has_feature(attribute_analyzer_noreturn) || \