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author | Bernhard Schommer <bernhardschommer@gmail.com> | 2023-01-09 15:53:30 +0100 |
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committer | Xavier Leroy <xavier.leroy@college-de-france.fr> | 2023-03-06 11:04:42 +0100 |
commit | a6e44cd88d2b37a7747d5057d04834c0deaa6601 (patch) | |
tree | 48cf6c88696cb05f93f50fa1d400a8903bfd911e /powerpc | |
parent | 30cb8bfbe8c4695a83b11cdaa409ccef1bac0395 (diff) | |
download | compcert-a6e44cd88d2b37a7747d5057d04834c0deaa6601.tar.gz compcert-a6e44cd88d2b37a7747d5057d04834c0deaa6601.zip |
Change preference for new register in allocator
Currently, the register allocator picks caller-save registers in preference
to callee-save registers.
But for ARM in Thumb mode, more compact code is obtained if we prefer
integer registers R0...R3 rather than all integer caller-save registers.
This commit introduces an `allocatable_registers` function in
$ARCH/Conventions1.v that determines the preferred and remaining
registers to be used for register allocation.
Diffstat (limited to 'powerpc')
-rw-r--r-- | powerpc/Conventions1.v | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/powerpc/Conventions1.v b/powerpc/Conventions1.v index f05e77df..2b93e1d8 100644 --- a/powerpc/Conventions1.v +++ b/powerpc/Conventions1.v @@ -91,6 +91,23 @@ Definition float_callee_save_regs := Definition dummy_int_reg := R3. (**r Used in [Coloring]. *) Definition dummy_float_reg := F0. (**r Used in [Coloring]. *) +(** How to use registers for register allocation. + We favor the use of caller-save registers, using callee-save registers + only when no caller-save is available. *) + +Record alloc_regs := mk_alloc_regs { + preferred_int_regs: list mreg; + remaining_int_regs: list mreg; + preferred_float_regs: list mreg; + remaining_float_regs: list mreg +}. + +Definition allocatable_registers (_: unit) := + {| preferred_int_regs := int_caller_save_regs; + remaining_int_regs := int_callee_save_regs; + preferred_float_regs := float_caller_save_regs; + remaining_float_regs := float_callee_save_regs |}. + (** * Function calling conventions *) (** The functions in this section determine the locations (machine registers |