add test for constant evaluation of vectors

Author: ficol

clang/test/AST/const-fpfeatures.c

@@ -22,6 +22,12 @@ float _Complex C1u = C0;
 float FLu = 0.1F;
 // CHECK: @FLu = {{.*}} float 0x3FB99999A0000000
 
+typedef float  vector2float  __attribute__((__vector_size__(8)));
+typedef double vector2double  __attribute__((__vector_size__(16)));
+const vector2float V2Fu = {1.0F + 0x0.000001p0F, 1.0F + 0x0.000002p0F};
+vector2double V2Du = __builtin_convertvector(V2Fu, vector2double);
+// CHECK: @V2Fu = {{.*}} <2 x float> splat (float 0x3FF0000020000000)
+// CHECK: @V2Du = {{.*}} <2 x double> splat (double 0x3FF0000020000000)
 
 #pragma STDC FENV_ROUND FE_DOWNWARD
 
@@ -41,3 +47,8 @@ float _Complex C1d = C0;
 
 float FLd = 0.1F;
 // CHECK: @FLd = {{.*}} float 0x3FB9999980000000
+
+const vector2float V2Fd = {1.0F + 0x0.000001p0F, 1.0F + 0x0.000002p0F};
+vector2double V2Dd = __builtin_convertvector(V2Fd, vector2double);
+// CHECK: @V2Fd = {{.*}} <2 x float> <float 1.000000e+00, float 0x3FF0000020000000>
+// CHECK: @V2Dd = {{.*}} <2 x double> <double 1.000000e+00, double 0x3FF0000020000000>