On Thu, Jun 22, 2023 at 1:42 AM Thiago Jung Bauermann <thiago.bauerm...@linaro.org> wrote: > > > Hello, > > Jeff Law <jeffreya...@gmail.com> writes: > > > On 6/19/23 22:52, Tamar Christina wrote: > > > >>> It's a bit hackish, but could we reject the stack pointer for operand1 in > >>> the > >>> stack-tie? And if we do so, does it help? > >> Yeah this one I had to defer until later this week to look at closer > >> because what I'm > >> wondering about is whether the optimization should apply to frame related > >> RTX as well. > >> Looking at the description of RTX_FRAME_RELATED_P that this optimization > >> may > >> end up de-optimizing RISC targets by creating an offset that is larger > >> than offset > >> which can be used from a SP making reload having to spill. i.e. sometimes > >> the > >> move was explicitly done. So perhaps it should not apply it to > >> RTX_FRAME_RELATED_P in find_oldest_value_reg and > >> copyprop_hardreg_forward_1? > >> Other parts of this pass already seems to bail out in similar situations. > >> So I needed > >> to > >> write some testcases to check what would happen in these cases hence the > >> deferral. > >> to later in the week. > > Rejecting for RTX_FRAME_RELATED_P would seem reasonable and probably better > > in general to > > me. The cases where we're looking to clean things up aren't really in the > > prologue/epilogue, but instead in the main body after register elimination > > has turned fp > > into sp + offset, thus making all kinds of things no longer valid. > > The problems I reported were fixed by commits: > > 580b74a79146 "aarch64: Robustify stack tie handling" > 079f31c55318 "aarch64: Fix gcc.target/aarch64/sve/pcs failures" > > Thanks! > > But unfortunately I'm still seeing bootstrap failures (ICE segmentation > fault) in today's trunk with build config bootstrap-lto in both > armv8l-linux-gnueabihf and aarch64-linux-gnu.
If there's not yet a bugreport for this please make sure to open one so this issue doesn't get lost. > If I revert commit 6a2e8dcbbd4b "cprop_hardreg: Enable propagation of > the stack pointer if possible" from trunk then both bootstraps succeed. > > Here's the command I'm using to build on armv8l: > > ~/src/configure \ > SHELL=/bin/bash \ > --with-gnu-as \ > --with-gnu-ld \ > --disable-libmudflap \ > --enable-lto \ > --enable-shared \ > --without-included-gettext \ > --enable-nls \ > --with-system-zlib \ > --disable-sjlj-exceptions \ > --enable-gnu-unique-object \ > --enable-linker-build-id \ > --disable-libstdcxx-pch \ > --enable-c99 \ > --enable-clocale=gnu \ > --enable-libstdcxx-debug \ > --enable-long-long \ > --with-cloog=no \ > --with-ppl=no \ > --with-isl=no \ > --disable-multilib \ > --with-float=hard \ > --with-fpu=neon-fp-armv8 \ > --with-mode=thumb \ > --with-arch=armv8-a \ > --enable-threads=posix \ > --enable-multiarch \ > --enable-libstdcxx-time=yes \ > --enable-gnu-indirect-function \ > --disable-werror \ > --enable-checking=yes \ > --enable-bootstrap \ > --with-build-config=bootstrap-lto \ > --enable-languages=c,c++,fortran,lto \ > && make \ > profiledbootstrap \ > SHELL=/bin/bash \ > -w \ > -j 40 \ > CFLAGS_FOR_BUILD="-pipe -g -O2" \ > CXXFLAGS_FOR_BUILD="-pipe -g -O2" \ > LDFLAGS_FOR_BUILD="-static-libgcc" \ > MAKEINFOFLAGS=--force \ > BUILD_INFO="" \ > MAKEINFO=echo > > And here's the slightly different one for aarch64-linux: > > ~/src/configure \ > SHELL=/bin/bash \ > --with-gnu-as \ > --with-gnu-ld \ > --disable-libmudflap \ > --enable-lto \ > --enable-shared \ > --without-included-gettext \ > --enable-nls \ > --with-system-zlib \ > --disable-sjlj-exceptions \ > --enable-gnu-unique-object \ > --enable-linker-build-id \ > --disable-libstdcxx-pch \ > --enable-c99 \ > --enable-clocale=gnu \ > --enable-libstdcxx-debug \ > --enable-long-long \ > --with-cloog=no \ > --with-ppl=no \ > --with-isl=no \ > --disable-multilib \ > --enable-fix-cortex-a53-835769 \ > --enable-fix-cortex-a53-843419 \ > --with-arch=armv8-a \ > --enable-threads=posix \ > --enable-multiarch \ > --enable-libstdcxx-time=yes \ > --enable-gnu-indirect-function \ > --disable-werror \ > --enable-checking=yes \ > --enable-bootstrap \ > --with-build-config=bootstrap-lto \ > --enable-languages=c,c++,fortran,lto \ > && make \ > profiledbootstrap \ > SHELL=/bin/bash \ > -w \ > -j 40 \ > LDFLAGS_FOR_TARGET="-Wl,-fix-cortex-a53-843419" \ > CFLAGS_FOR_BUILD="-pipe -g -O2" \ > CXXFLAGS_FOR_BUILD="-pipe -g -O2" \ > LDFLAGS_FOR_BUILD="-static-libgcc" \ > MAKEINFOFLAGS=--force \ > BUILD_INFO="" \ > MAKEINFO=echo > > -- > Thiago
