[llvm] [SPIRV] Fix code quality issues. (PR #152005)

[Nathan Gauër via llvm-commits]

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@@ -893,9 +893,11 @@ Type *SPIRVEmitIntrinsics::deduceNestedTypeHelper(
     bool Change = false;
     for (unsigned i = 0; i < U->getNumOperands(); ++i) {
       Value *Op = U->getOperand(i);
-      Type *OpTy = Op->getType();
-      Type *Ty = OpTy;
+      Type *OpTy = nullptr;
+      Type *Ty = nullptr;
       if (Op) {
+        OpTy = Op->getType();
+        Ty = OpTy;
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Keenuts wrote:

This looks wrong.
-> We use `U->getNumOperands()` and then index using this bounded value. Meaning if we get a `nullptr` operand, something is wrong.
I would maybe `assert(OpTy)`, but setting `Ty` to nullptr as-is means we expect some operands to be null and that we could push nullptr to `Tys`, which seems wrong.

https://github.com/llvm/llvm-project/pull/152005