[llvm] [SPIRV] Added support for the constrained arithmetic intrinsic (PR #157441)

[Matt Arsenault via llvm-commits]

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@@ -1193,6 +1199,37 @@ bool SPIRVInstructionSelector::selectOpWithSrcs(Register ResVReg,
   return MIB.constrainAllUses(TII, TRI, RBI);
 }
 
+bool SPIRVInstructionSelector::selectStrictFMulAdd(Register ResVReg,
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arsenm wrote:

In this case there's no value in reporting it as legal. I'd expect to just use .lower() and have it break into the separate operations 

https://github.com/llvm/llvm-project/pull/157441