[llvm] [SPIR-V] Add --spirv-fp-contract option to control kernel ContractionOff emission (PR #206404)

[Juan Manuel Martinez Caamaño via llvm-commits]

================
@@ -37,13 +37,30 @@
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
 #define DEBUG_TYPE "asm-printer"
 
+namespace {
+enum class SPIRVFPContractMode { On, Off, Fast };
+} // namespace
+
+static cl::opt<SPIRVFPContractMode> SPIRVFPContract(
+    "spirv-fp-contract",
+    cl::desc("Override FP contraction policy for SPIR-V kernel entry points"),
+    cl::values(
+        clEnumValN(SPIRVFPContractMode::On, "on",
+                   "Follow IR metadata (default)"),
+        clEnumValN(SPIRVFPContractMode::Off, "off",
+                   "Force ContractionOff on all kernel entry points"),
+        clEnumValN(SPIRVFPContractMode::Fast, "fast",
+                   "Suppress ContractionOff on all kernel entry points")),
+    cl::init(SPIRVFPContractMode::On));
+
 namespace {
----------------
jmmartinez wrote:

We could merge the 2 anonymous namespaces:

```suggestion
namespace {
enum class SPIRVFPContractMode { On, Off, Fast };

static cl::opt<SPIRVFPContractMode> SPIRVFPContract(
    "spirv-fp-contract",
    cl::desc("Override FP contraction policy for SPIR-V kernel entry points"),
    cl::values(
        clEnumValN(SPIRVFPContractMode::On, "on",
                   "Follow IR metadata (default)"),
        clEnumValN(SPIRVFPContractMode::Off, "off",
                   "Force ContractionOff on all kernel entry points"),
        clEnumValN(SPIRVFPContractMode::Fast, "fast",
                   "Suppress ContractionOff on all kernel entry points")),
    cl::init(SPIRVFPContractMode::On));

```

https://github.com/llvm/llvm-project/pull/206404