[llvm] [C API] Add getters and setters for fast-math flags on relevant instructions (PR #75123)

[Nikita Popov via llvm-commits]

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@@ -770,8 +770,19 @@ struct FunCloner {
         }
 
         LLVMAddIncoming(Dst, Values.data(), Blocks.data(), IncomingCount);
+        if (LLVMGetCanUseFastMathFlags(Src))
+          LLVMSetFastMathFlags(Dst, LLVMGetFastMathFlags(Src));
         return Dst;
       }
+      case LLVMSelect: {
+        LLVMValueRef If = CloneValue(LLVMGetOperand(Src, 0));
+        LLVMValueRef Then = CloneValue(LLVMGetOperand(Src, 1));
+        LLVMValueRef Else = CloneValue(LLVMGetOperand(Src, 2));
+        Dst = LLVMBuildSelect(Builder, If, Then, Else, Name);
+        if (LLVMGetCanUseFastMathFlags(Src))
+          LLVMSetFastMathFlags(Dst, LLVMGetFastMathFlags(Src));
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nikic wrote:

Rather than adding this to specific cases (and having to list out all the FP instructions), can we do this once after the switch?

https://github.com/llvm/llvm-project/pull/75123