CODEWITHSUNDEEP
bytecodespir-v
Fox1942
Fox1942

Reputation: 366

How to change result type id while reserving the literal value of OpConstant in Spir-V?

I am writing a Spir-v processor, which is intended to create a new OpTypeFloat with a width of 16 bits and then change the result type ids of the existing OpConstants to the result id of the created, new OpTypeFloat. Practically, I want to change fp32 variables to fp16.

Here is the code snippet, which deals with this.

ir.for_each_typed_id<spirv_cross::SPIRConstant>([&](uint32_t id, spirv_cross::SPIRConstant& constant) {
    auto type = compiler.get_type(constant.constant_type);

    if (type.op != spv::OpTypeFloat || type.width != 32) {
        return;
    }

    auto instruction = constant_id_to_instruction_mapping[id];
    data[instruction.offset] = newtypeid;
});

To print out the spir-v, I am using this code:

spv_text text = nullptr;
  spv_diagnostic diagnostic = nullptr;
  spvBinaryToText(spvContextCreate(SPV_ENV_UNIVERSAL_1_0), data, bytecode.size(), SPV_BINARY_TO_TEXT_OPTION_INDENT, &text, &diagnostic);
  printf("%s", text->str);
  spvTextDestroy(text);

This is from the original Spir-V:

 %10 = OpTypeFloat 16
 %9 = OpConstant %6 0.5

This is after the processing:

%10 = OpTypeFloat 16
%9 = OpConstant %10 0x0p+0

As you can see after the code, I got 0x0p+0 for the literal value, not 0.5 like previously. Btw, if I print out the value from console, I got the right number.

So, What causes the problem? I bet that, spvBinaryToText method interprets things differently, in case of changing the result type id of the OpConstant.

Upvotes: 0

Views: 11

Answers (0)

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