[clang][bytecode] Cast fixed-point cmp result to int if necessary (#110469)

This is the case in C.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -1542,19 +1542,30 @@ bool Compiler<Emitter>::VisitFixedPointBinOp(const BinaryOperator *E) {
     return true;
   };
 
+  auto MaybeCastToBool = [&](bool Result) {
+    if (!Result)
+      return false;
+    PrimType T = classifyPrim(E);
+    if (DiscardResult)
+      return this->emitPop(T, E);
+    if (T != PT_Bool)
+      return this->emitCast(PT_Bool, T, E);
+    return true;
+  };
+
   switch (E->getOpcode()) {
   case BO_EQ:
-    return this->emitEQFixedPoint(E);
+    return MaybeCastToBool(this->emitEQFixedPoint(E));
   case BO_NE:
-    return this->emitNEFixedPoint(E);
+    return MaybeCastToBool(this->emitNEFixedPoint(E));
   case BO_LT:
-    return this->emitLTFixedPoint(E);
+    return MaybeCastToBool(this->emitLTFixedPoint(E));
   case BO_LE:
-    return this->emitLEFixedPoint(E);
+    return MaybeCastToBool(this->emitLEFixedPoint(E));
   case BO_GT:
-    return this->emitGTFixedPoint(E);
+    return MaybeCastToBool(this->emitGTFixedPoint(E));
   case BO_GE:
-    return this->emitGEFixedPoint(E);
+    return MaybeCastToBool(this->emitGEFixedPoint(E));
   case BO_Add:
     return ConvertResult(this->emitAddFixedPoint(E));
   case BO_Sub:

clang/test/Frontend/fixed_point_comparisons.c

@@ -1,6 +1,9 @@
 // RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,UNPADDED
 // RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -fpadding-on-unsigned-fixed-point -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,PADDED
 
+// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - -fexperimental-new-constant-interpreter | FileCheck %s --check-prefixes=CHECK,UNPADDED
+// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -fpadding-on-unsigned-fixed-point -emit-llvm %s -o - -fexperimental-new-constant-interpreter | FileCheck %s --check-prefixes=CHECK,PADDED
+
 // Fixed point against other fixed point
 _Bool b_eq_true = 2.5hk == 2.5uhk;  // CHECK-DAG: @b_eq_true  = {{.*}}global i8 1, align 1
 _Bool b_eq_false = 2.5hk == 2.4uhk; // CHECK-DAG: @b_eq_false = {{.*}}global i8 0, align 1