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| author | Georg-Johann Lay <avr@gjlay.de> | 2025-01-22 21:11:22 +0100 |
|---|---|---|
| committer | Georg-Johann Lay <avr@gjlay.de> | 2025-01-23 10:13:42 +0100 |
| commit | f30edd17e62e9474f90785a5915959cd6d8c3f62 (patch) | |
| tree | b9fe8cf33cbb603a2b19b7b7beca1702d204e187 /gcc/config/openbsd-rust.cc | |
| parent | b3f51ea894947e495baffc67407647a3b25acdd5 (diff) | |
| download | gcc-f30edd17e62e9474f90785a5915959cd6d8c3f62.zip gcc-f30edd17e62e9474f90785a5915959cd6d8c3f62.tar.gz gcc-f30edd17e62e9474f90785a5915959cd6d8c3f62.tar.bz2 | |
AVR: PR117726 - Tweak 32-bit logical shifts of 25...30 for -Oz.
As it turns out, logical 32-bit shifts with an offset of 25..30 can
be performed in 7 instructions or less. This beats the 7 instruc-
tions required for the default code of a shift loop.
Plus, with zero overhead, these cases can be 3-operand.
This is only relevant for -Oz because with -Os, 3op shifts are
split with -msplit-bit-shift (which is not performed with -Oz).
PR target/117726
gcc/
* config/avr/avr.cc (avr_ld_regno_p): New function.
(ashlsi3_out) [case 25,26,27,28,29,30]: Handle and tweak.
(lshrsi3_out): Same.
(avr_rtx_costs_1) [SImode, ASHIFT, LSHIFTRT]: Adjust costs.
* config/avr/avr.md (ashlsi3, *ashlsi3, *ashlsi3_const):
Add "r,r,C4L" alternative.
(lshrsi3, *lshrsi3, *lshrsi3_const): Add "r,r,C4R" alternative.
* config/avr/constraints.md (C4R, C4L): New,
gcc/testsuite/
* gcc.target/avr/torture/avr-torture.exp (AVR_TORTURE_OPTIONS):
Turn one option variant into -Oz.
Diffstat (limited to 'gcc/config/openbsd-rust.cc')
0 files changed, 0 insertions, 0 deletions