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.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190915 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 10d384b8d8..d68bdbb425 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4463,6 +4463,19 @@ ExprResult Sema::ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
                RParenLoc));
 }
 
+/// ActOnConvertVectorExpr - create a new convert-vector expression from the
+/// provided arguments.
+///
+/// __builtin_convertvector( value, dst type )
+///
+ExprResult Sema::ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
+                                        SourceLocation BuiltinLoc,
+                                        SourceLocation RParenLoc) {
+  TypeSourceInfo *TInfo;
+  GetTypeFromParser(ParsedDestTy, &TInfo);
+  return SemaConvertVectorExpr(E, TInfo, BuiltinLoc, RParenLoc);
+}
+
 /// BuildResolvedCallExpr - Build a call to a resolved expression,
 /// i.e. an expression not of \p OverloadTy.  The expression should
 /// unary-convert to an expression of function-pointer or