microsoft
Calling member function on raypayload causes `cast<X>() argument of incompatible type` error with PAQ
Description
When compiling the provided simple shader repro with SM6.7 or above (when PAQ is enabled by default) or with SM6.6 and compiling with -enable-payload-qualifiers, the compiler fails with an "Internal Compiler error".
It seems to be related to PAQ in combination with calling a member function on a raypayload that writes to a member.
Steps to Reproduce Example in Compiler Explorer: https://godbolt.org/z/qqKedsWv9 Commandlines that reproduce the issue:
-T lib_6_7-T lib_6_8-T lib_6_6 -enable-payload-qualifiers
Actual Behavior The output of the compiler:
Internal Compiler error: cast<X>() argument of incompatible type!
Compiler returned: 29
Environment
- DXC version
dxcompiler.dll: 1.8 - 1.8.2403.36 (9c2b82878); dxil.dll: 1.8(101.8.2403.21) - Host Operating System: Win11 - 22631.3296
A few bits of extra context. This reproduces back to DXC 1.7.2207 when targeting SM 6.7, so it is not a new regression. The call stack for the exception throw is:
An exception is being thrown from here, because a member function is being accessed but the code assumes all member accesses are field declarations.
This exposes a flaw in the implementation for payload access qualifiers. It incorrectly assumes all member expressions are accessing field declarations whereas here we're accessing a member function declaration.
Slightly reduced repro: https://godbolt.org/z/bnb9feMv6 - this repro doesn't have any payload qualifiers at all, although passing -enable-payload-qualifiers does trigger it.
Looks like this would affect someone trying to migrate from lib_6_6 to lib_6_7.
