[Matrix] Remove bitcast when casting between matrices of the same size

In matrix type casts, we were doing bitcast when the matrices had the same size. This was incorrect and this patch fixes that.
Also added some new CodeGen tests for signed <-> usigned conversions

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D101754

Author: SaurabhJha

clang/lib/CodeGen/CGExprScalar.cpp

@@ -1205,10 +1205,6 @@ Value *ScalarExprEmitter::EmitScalarCast(Value *Src, QualType SrcType,
   QualType SrcElementType;
   QualType DstElementType;
   if (SrcType->isMatrixType() && DstType->isMatrixType()) {
-    // Allow bitcast between matrixes of the same size.
-    if (SrcTy->getPrimitiveSizeInBits() == DstTy->getPrimitiveSizeInBits())
-      return Builder.CreateBitCast(Src, DstTy, "conv");
-
     SrcElementTy = cast<llvm::VectorType>(SrcTy)->getElementType();
     DstElementTy = cast<llvm::VectorType>(DstTy)->getElementType();
     SrcElementType = SrcType->castAs<MatrixType>()->getElementType();

clang/test/CodeGen/matrix-cast.c

@@ -52,13 +52,23 @@ void cast_int_matrix_to_short(ix5x5 i, sx5x5 s) {
 void cast_int_matrix_to_float(ix5x5 i, fx5x5 f) {
   // CHECK-LABEL: define{{.*}} void @cast_int_matrix_to_float(<25 x i32> %i, <25 x float> %f)
   // CHECK:       [[I:%.*]] = load <25 x i32>, <25 x i32>* {{.*}}, align 4
-  // CHECK-NEXT:  [[CONV:%.*]] = bitcast <25 x i32> [[I]] to <25 x float>
+  // CHECK-NEXT:  [[CONV:%.*]] = sitofp <25 x i32> [[I]] to <25 x float>
   // CHECK-NEXT:  store <25 x float> [[CONV]], <25 x float>* {{.*}}, align 4
   // CHECK-NEXT:  ret void
 
   f = (fx5x5)i;
 }
 
+void cast_unsigned_int_matrix_to_float(unsigned_short_int_5x5 u, fx5x5 f) {
+  // CHECK-LABEL: define{{.*}} void @cast_unsigned_int_matrix_to_float(<25 x i16> %u, <25 x float> %f)
+  // CHECK:       [[U:%.*]] = load <25 x i16>, <25 x i16>* {{.*}}, align 2
+  // CHECK-NEXT:  [[CONV:%.*]] = uitofp <25 x i16> [[U]] to <25 x float>
+  // CHECK-NEXT:  store <25 x float> [[CONV]], <25 x float>* {{.*}}, align 4
+  // CHECK-NEXT:  ret void
+
+  f = (fx5x5)u;
+}
+
 void cast_double_matrix_to_int(dx5x5 d, ix5x5 i) {
   // CHECK-LABEL: define{{.*}} void @cast_double_matrix_to_int(<25 x double> %d, <25 x i32> %i)
   // CHECK:       [[D:%.*]] = load <25 x double>, <25 x double>* {{.*}}, align 8
@@ -108,3 +118,23 @@ void cast_unsigned_long_int_to_unsigned_short_int(unsigned_long_int_5x5 l, unsig
 
   s = (unsigned_short_int_5x5)l;
 }
+
+void cast_unsigned_short_int_to_int(unsigned_short_int_5x5 u, ix5x5 i) {
+  // CHECK-LABEL: define{{.*}} void @cast_unsigned_short_int_to_int(<25 x i16> %u, <25 x i32> %i)
+  // CHECK:       [[U:%.*]] = load <25 x i16>, <25 x i16>* %0, align 2
+  // CHECK-NEXT:  [[CONV:%.*]] = zext <25 x i16> [[U]] to <25 x i32>
+  // CHECK-NEXT:  store <25 x i32> [[CONV]], <25 x i32>* {{.*}}, align 4
+  // CHECK-NEXT:  ret void
+
+  i = (ix5x5)u;
+}
+
+void cast_int_to_unsigned_long_int(ix5x5 i, unsigned_long_int_5x5 u) {
+  // CHECK-LABEL: define{{.*}} void @cast_int_to_unsigned_long_int(<25 x i32> %i, <25 x i64> %u)
+  // CHECK:       [[I:%.*]] = load <25 x i32>, <25 x i32>* %0, align 4
+  // CHECK-NEXT:  [[CONV:%.*]] = sext <25 x i32> [[I]] to <25 x i64>
+  // CHECK-NEXT:  store <25 x i64> [[CONV]], <25 x i64>* {{.*}}, align 8
+  // CHECK-NEXT:  ret void
+
+  u = (unsigned_long_int_5x5)i;
+}