[Backport to 17] Generate load and store for OpCopyLogical (#2825)

fixes #2768

Generate an LLVM memcpy for OpCopyLogical, rather than a call to an OpCopyLogical function.

(cherry picked from commit 1a1bf17)

Author: bashbaug

lib/SPIRV/SPIRVReader.cpp

@@ -2232,7 +2232,22 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
   }
   case OpCopyLogical: {
     SPIRVCopyLogical *CL = static_cast<SPIRVCopyLogical *>(BV);
-    return mapValue(BV, transSPIRVBuiltinFromInst(CL, BB));
+
+    auto *SrcTy = transType(CL->getOperand()->getType());
+    auto *DstTy = transType(CL->getType());
+
+    assert(M->getDataLayout().getTypeStoreSize(SrcTy).getFixedValue() ==
+               M->getDataLayout().getTypeStoreSize(DstTy).getFixedValue() &&
+           "Size mismatch in OpCopyLogical");
+
+    IRBuilder<> Builder(BB);
+
+    auto *SrcAI = Builder.CreateAlloca(SrcTy);
+    Builder.CreateAlignedStore(transValue(CL->getOperand(), F, BB), SrcAI,
+                               SrcAI->getAlign());
+
+    auto *LI = Builder.CreateAlignedLoad(DstTy, SrcAI, SrcAI->getAlign());
+    return mapValue(BV, LI);
   }
 
   case OpAccessChain:

test/OpCopyLogical.spvasm

@@ -22,4 +22,6 @@
                OpReturn
                OpFunctionEnd
 
-; CHECK-LLVM: @_Z19__spirv_CopyLogical12structtype.0(ptr sret(%structtype) %[[#]], %structtype.0 zeroinitializer)
+; CHECK-LLVM: [[ALLOCA:%[a-z0-9.]+]] = alloca [[SRC_TYPE:%[a-z0-9.]+]], align 8
+; CHECK-LLVM: store [[SRC_TYPE]] zeroinitializer, ptr [[ALLOCA]], align 8
+; CHECK-LLVM: [[DST:%[a-z0-9.]+]] = load [[DST_TYPE:%[a-z0-9.]+]], ptr [[ALLOCA]], align 8