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JULY 29, 2026
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gcc/rs6000

Add __dmr1024 opaque type for dense math registers

Introduces a new 1024-bit opaque type for the Dense Math Facility on POWER.

This commit registers __dmr1024 as a new 1024-bit opaque built-in type for the rs6000 backend. It uses TDOmode and is intended to hold data for the Dense Math Facility when the -mdense-math option is enabled, with specific handling for type mangling and invalid conversions.

In Details

Registers __dmr1024 as a new opaque type using TDOmode, aligned to 512 bits. This type is gated by TARGET_DMF and requires -mdense-math. It's meant to hold Dense Math Register (DMR) contents, complementing existing vector types and requiring specific handling in type string mangling and conversion checks.

For Context
opaque type
A data type whose internal structure is not exposed to the user, often used for hardware-specific registers or abstractions.
TDOmode
A GCC target-mode representing a specific data type or register size, in this case for dense math registers.
Dense Math Facility
A hardware feature on POWER processors for enhanced floating-point and vector operations.
-mdense-math
A GCC command-line option that enables the use of the Dense Math Facility on POWER architectures.
type mangling
The process of altering a function or type name to include information about its parameters and return type, used by linkers and compilers to support function overloading and type safety.
Filed Under: rs6000powerpcnew-typedense-math