[llvm] [SPIRV] Implement log10 for logical SPIR-V (PR #66921)

[Natalie Chouinard via llvm-commits]

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@@ -260,8 +260,18 @@ Register SPIRVGlobalRegistry::buildConstantFP(APFloat Val,
     MF.getRegInfo().setRegClass(Res, &SPIRV::IDRegClass);
     assignTypeToVReg(LLVMFPTy, Res, MIRBuilder);
     DT.add(ConstFP, &MF, Res);
-    MIRBuilder.buildFConstant(Res, *ConstFP);
+    if (EmitIR) {
+      MIRBuilder.buildFConstant(Res, *ConstFP);
+    } else {
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sudonatalie wrote:

If I understand things correctly, GlobalISel (where this function is called from) *is* the process that does that lowering from gMIR (generic MIR) to MIR (SPIR-V specific opcodes). If we don't lower it here, it doesn't happen and gets to the writer without having been lowered, causing a `"Cannot print this instruction."` failure in `SPIRVGenAsmWriter.inc`.

https://github.com/llvm/llvm-project/pull/66921