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| author | Segher Boessenkool <segher@kernel.crashing.org> | 2017-08-09 23:08:33 +0200 |
|---|---|---|
| committer | Segher Boessenkool <segher@gcc.gnu.org> | 2017-08-09 23:08:33 +0200 |
| commit | cc6a467f450424a14bfc71d03e83b3981f4fc864 (patch) | |
| tree | 8630b82450ca497021fe09a477cf138ac39daa8f /gcc | |
| parent | a8a581af9ec2c7c774b5309d9d4e6555ddfc440b (diff) | |
| download | gcc-cc6a467f450424a14bfc71d03e83b3981f4fc864.zip gcc-cc6a467f450424a14bfc71d03e83b3981f4fc864.tar.gz gcc-cc6a467f450424a14bfc71d03e83b3981f4fc864.tar.bz2 | |
rs6000: Use SAVE_MULTIPLE only if we restore what it saves (PR80938)
We can have SAVE_MULTIPLE while we do not have REST_MULTIPLE. If the
inline restore does not restore all registers, the CFI for the save
and restore can conflict if things are shrink-wrapped.
We could restore all registers that are saved (not ideal), or emit
the CFI notes to say we did (which will work fine, but is also not
so great); instead, let's not save the registers that are unused.
PR target/80938
* config/rs6000/rs6000.c (rs6000_savres_strategy): Don't use
SAVE_MULTIPLE if not all the registers that saves, should be saved.
From-SVN: r251005
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/config/rs6000/rs6000.c | 15 |
2 files changed, 21 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d3f9d2d..f69aeed 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-08-09 Segher Boessenkool <segher@kernel.crashing.org> + + PR target/80938 + * config/rs6000/rs6000.c (rs6000_savres_strategy): Don't use + SAVE_MULTIPLE if not all the registers that saves, should be saved. + 2017-08-09 Jim Wilson <jim.wilson@linaro.org> * config/aarch64/aarch64-cores.def (falkor): Use falkor pipeline. diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 1fb9861..8f502db 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -24431,6 +24431,21 @@ rs6000_savres_strategy (rs6000_stack_t *info, else if (!lr_save_p && info->first_gp_reg_save > 29) strategy |= SAVE_INLINE_GPRS | REST_INLINE_GPRS; + /* We can only use save multiple if we need to save all the registers from + first_gp_reg_save. Otherwise, the CFI gets messed up (we save some + register we do not restore). */ + if (strategy & SAVE_MULTIPLE) + { + int i; + + for (i = info->first_gp_reg_save; i < 32; i++) + if (fixed_reg_p (i) || !save_reg_p (i)) + { + strategy &= ~SAVE_MULTIPLE; + break; + } + } + /* We can only use load multiple or the out-of-line routines to restore gprs if we've saved all the registers from first_gp_reg_save. Otherwise, we risk loading garbage. |