[Bug target/80938] [7/8 Regression] ICE in maybe_record_trace_start, at dwarf2cfi.c:2330
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80938 --- Comment #8 from Aldy Hernandez --- Author: aldyh Date: Wed Sep 13 17:04:04 2017 New Revision: 252454 URL: https://gcc.gnu.org/viewcvs?rev=252454=gcc=rev Log: [RS6000] PR 80938, Don't emit frame info for regs that don't need saving It is possible when using out-of-line register saves or store multiple to save some registers unnecessarily, for example one reg in the block saved might be unused. We don't need to emit frame info for those registers as that just bloats the info, and also can result in an ICE when shrink-wrap gives multiple paths through the function saving different sets of registers. Join points need to have identical frame register save state regardless of the path taken. This patch reverts the previous fix for PR80939 "Use SAVE_MULTIPLE only if we restore what it saves (PR80938)" and instead fixes the PR by correcting the frame info. The change to rs6000_savres_strategy is an optimization, but note that it hides the underlying problem in the PR testcase. PR target/80938 * config/rs6000/rs6000.c (rs6000_savres_strategy): Revert 2017-08-09. Don't use store multiple if only one reg needs saving. (interesting_frame_related_regno): New function. (rs6000_frame_related): Don't emit frame info for regs that don't need saving. (rs6000_emit_epilogue): Likewise. Modified: branches/range-gen2/gcc/ChangeLog branches/range-gen2/gcc/config/rs6000/rs6000.c
[Bug target/80938] [7/8 Regression] ICE in maybe_record_trace_start, at dwarf2cfi.c:2330
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80938 --- Comment #7 from Aldy Hernandez --- Author: aldyh Date: Wed Sep 13 16:44:59 2017 New Revision: 252367 URL: https://gcc.gnu.org/viewcvs?rev=252367=gcc=rev Log: 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. Modified: branches/range-gen2/gcc/ChangeLog branches/range-gen2/gcc/config/rs6000/rs6000.c
[Bug target/80938] [7/8 Regression] ICE in maybe_record_trace_start, at dwarf2cfi.c:2330
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80938 --- Comment #6 from Alan Modra --- Author: amodra Date: Thu Aug 17 02:03:03 2017 New Revision: 251140 URL: https://gcc.gnu.org/viewcvs?rev=251140=gcc=rev Log: [RS6000] PR 80938, Don't emit frame info for regs that don't need saving It is possible when using out-of-line register saves or store multiple to save some registers unnecessarily, for example one reg in the block saved might be unused. We don't need to emit frame info for those registers as that just bloats the info, and also can result in an ICE when shrink-wrap gives multiple paths through the function saving different sets of registers. Join points need to have identical frame register save state regardless of the path taken. This patch reverts the previous fix for PR80939 "Use SAVE_MULTIPLE only if we restore what it saves (PR80938)" and instead fixes the PR by correcting the frame info. The change to rs6000_savres_strategy is an optimization, but note that it hides the underlying problem in the PR testcase. PR target/80938 * config/rs6000/rs6000.c (rs6000_savres_strategy): Revert 2017-08-09. Don't use store multiple if only one reg needs saving. (interesting_frame_related_regno): New function. (rs6000_frame_related): Don't emit frame info for regs that don't need saving. (rs6000_emit_epilogue): Likewise. Modified: trunk/gcc/ChangeLog trunk/gcc/config/rs6000/rs6000.c
[Bug target/80938] [7/8 Regression] ICE in maybe_record_trace_start, at dwarf2cfi.c:2330
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80938 --- Comment #5 from Segher Boessenkool --- Fixed on trunk for rs6000; backports pending.
[Bug target/80938] [7/8 Regression] ICE in maybe_record_trace_start, at dwarf2cfi.c:2330
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80938 --- Comment #4 from Segher Boessenkool --- Author: segher Date: Wed Aug 9 21:08:33 2017 New Revision: 251005 URL: https://gcc.gnu.org/viewcvs?rev=251005=gcc=rev Log: 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. Modified: trunk/gcc/ChangeLog trunk/gcc/config/rs6000/rs6000.c
