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| author | YunQiang Su <yunqiang.su@cipunited.com> | 2021-05-08 05:45:53 -0400 |
|---|---|---|
| committer | YunQiang Su <yunqiang.su@cipunited.com> | 2022-10-25 16:44:09 +0800 |
| commit | 4479f1dc79fc4f1b5e0fed209df35f405bc94589 (patch) | |
| tree | ede450fd98bcdba7902a3d01ca0759c5f5a9a2e1 /gcc/doc | |
| parent | 7d888535f7ab80e9b08a633bfd774a923b311cde (diff) | |
| download | gcc-4479f1dc79fc4f1b5e0fed209df35f405bc94589.zip gcc-4479f1dc79fc4f1b5e0fed209df35f405bc94589.tar.gz gcc-4479f1dc79fc4f1b5e0fed209df35f405bc94589.tar.bz2 | |
MIPS: Not trigger error for pre-R6 and -mcompact-branches=always
For MIPSr6, we may wish to use compact-branches only.
Currently, we have to use `always' option, while it is mark as conflict
with pre-R6.
cc1: error: unsupported combination: ‘mips32r2’ -mcompact-branches=always
Just ignore -mcompact-branches=always for pre-R6.
This patch also defines
__mips_compact_branches_never
__mips_compact_branches_always
__mips_compact_branches_optimal
predefined macros
gcc/ChangeLog:
* config/mips/mips.cc (mips_option_override): not trigger error
for compact-branches=always for pre-R6.
* config/mips/mips.h (TARGET_RTP_PIC): not trigger error for
compact-branches=always for pre-R6.
(TARGET_CB_NEVER): Likewise.
(TARGET_CB_ALWAYS): Likewise.
(struct mips_cpu_info): define macros for compact branch policy.
* doc/invoke.texi: Document "always" with pre-R6.
gcc/testsuite/ChangeLog:
* gcc.target/mips/compact-branches-1.c: add isa_rev>=6.
* gcc.target/mips/mips.exp: don't add -mipsXXr6 option for
-mcompact-branches=always. It is usable for pre-R6 now.
* gcc.target/mips/compact-branches-8.c: New test.
* gcc.target/mips/compact-branches-9.c: New test.
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/invoke.texi | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index d49c137..64f77e8 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -27091,11 +27091,13 @@ The @option{-mcompact-branches=never} option ensures that compact branch instructions will never be generated. The @option{-mcompact-branches=always} option ensures that a compact -branch instruction will be generated if available. If a compact branch -instruction is not available, a delay slot form of the branch will be -used instead. +branch instruction will be generated if available for MIPS Release 6 onwards. +If a compact branch instruction is not available (or pre-R6), +a delay slot form of the branch will be used instead. -This option is supported from MIPS Release 6 onwards. +If it is used for MIPS16/microMIPS targets, it will be just ignored now. +The behaviour for MIPS16/microMIPS may change in future, +since they do have some compact branch instructions. The @option{-mcompact-branches=optimal} option will cause a delay slot branch to be used if one is available in the current ISA and the delay |