[CIR] Upstream floating point literal expressions (llvm#129304)

This change adds support for floating point literal expressions

Author: AmrDeveloper

clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp

@@ -74,6 +74,15 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
         builder.getAttr<cir::IntAttr>(type, e->getValue()));
   }
 
+  mlir::Value VisitFloatingLiteral(const FloatingLiteral *e) {
+    mlir::Type type = cgf.convertType(e->getType());
+    assert(mlir::isa<cir::CIRFPTypeInterface>(type) &&
+           "expect floating-point type");
+    return builder.create<cir::ConstantOp>(
+        cgf.getLoc(e->getExprLoc()), type,
+        builder.getAttr<cir::FPAttr>(type, e->getValue()));
+  }
+
   mlir::Value VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *e) {
     mlir::Type type = cgf.convertType(e->getType());
     return builder.create<cir::ConstantOp>(

clang/test/CIR/func-simple.cpp

@@ -57,3 +57,15 @@ bool boolfunc() { return true; }
 // CHECK:   %0 = cir.const #true
 // CHECK:   cir.return %0 : !cir.bool
 // CHECK: }
+
+float floatfunc() { return 42.42f; }
+// CHECK: cir.func @floatfunc() -> !cir.float {
+// CHECK:   %0 = cir.const #cir.fp<4.242
+// CHECK:   cir.return %0 : !cir.float
+// CHECK: }
+
+double doublefunc() { return 42.42; }
+// CHECK: cir.func @doublefunc() -> !cir.double {
+// CHECK:   %0 = cir.const #cir.fp<4.242
+// CHECK:   cir.return %0 : !cir.double
+// CHECK: }