[llvm] [SPIR-V] Add lowering for G_FSINCOS (PR #179053)

[Dmitry Sidorov via llvm-commits]

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@@ -1409,6 +1413,71 @@ bool SPIRVInstructionSelector::selectFrexp(Register ResVReg,
   return false;
 }
 
+bool SPIRVInstructionSelector::selectSincos(Register ResVReg,
+                                            const SPIRVType *ResType,
+                                            MachineInstr &I) const {
+  Register CosResVReg = I.getOperand(1).getReg();
+  unsigned SrcIdx = I.getNumExplicitDefs();
+  Register ResTypeReg = GR.getSPIRVTypeID(ResType);
+
+  if (STI.canUseExtInstSet(SPIRV::InstructionSet::OpenCL_std)) {
+    // OpenCL.std sincos(x, cosval*) -> returns sin(x), writes cos(x) to ptr.
+    MachineIRBuilder MIRBuilder(I);
+    const SPIRVType *PointerType = GR.getOrCreateSPIRVPointerType(
+        ResType, MIRBuilder, SPIRV::StorageClass::Function);
+    Register PointerVReg =
+        createVirtualRegister(PointerType, &GR, MRI, MRI->getMF());
+
+    auto It = getOpVariableMBBIt(I);
+    auto MIB = BuildMI(*It->getParent(), It, It->getDebugLoc(),
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MrSidims wrote:

Yeah, I also find this a bit confusing, but that is the style of other functions in the file, so I used it. Applied your suggestion. 

https://github.com/llvm/llvm-project/pull/179053