From cc6a467f450424a14bfc71d03e83b3981f4fc864 Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Wed, 9 Aug 2017 23:08:33 +0200 Subject: [PATCH] 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 --- gcc/ChangeLog | 6 ++++++ gcc/config/rs6000/rs6000.c | 15 +++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d3f9d2d5150..f69aeed99d3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-08-09 Segher Boessenkool + + 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 * config/aarch64/aarch64-cores.def (falkor): Use falkor pipeline. diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 1fb98618186..8f502dbdf04 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. -- 2.30.2