[llvm] [GlobalISel] use constexpr LLT types when creating ISel data (PR #191574)

[Alan Li via llvm-commits]

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@@ -408,18 +408,44 @@ void LLTCodeGen::emitCxxEnumValue(raw_ostream &OS) const {
   llvm_unreachable("Unhandled LLT");
 }
 
+/// Emit a constexpr LLT constructor call for an IEEE floating-point type.
+/// Using specific constructors (float16, float32, etc.) instead of the generic
+/// floatIEEE() avoids static initialization order issues: floatIEEE() calls
+/// getUseExtended() which may return false during static init, producing
+/// LLT::scalar() instead of the intended float type.
+static void emitFloatIEEECxxConstructorCall(raw_ostream &OS,
+                                            unsigned SizeInBits) {
+  switch (SizeInBits) {
+  case 16:
+    OS << "LLT::float16()";
+    break;
+  case 32:
+    OS << "LLT::float32()";
+    break;
+  case 64:
+    OS << "LLT::float64()";
+    break;
+  case 128:
+    OS << "LLT::float128()";
+    break;
+  default:
+    OS << "LLT::floatIEEE(" << SizeInBits << ")";
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lialan wrote:

is this conflicting the function comment which says:
```
Using specific constructors (float16, float32, etc.) instead of the generic ... floatIEEE()
```

https://github.com/llvm/llvm-project/pull/191574