On Thu, 18 Jun 2026, Joseph Myers wrote: > On Tue, 16 Jun 2026, Andrew Pinski wrote: > > > From: Carter Rennick <[email protected]> > > > > The definition of MAX_FIXED_MODE_SIZE did not account for MIPS supporting > > TImode, which causes an internal compiler error when building libstdc++. > > Upon further > > investigation, this definition appears to be a historical mistake. > > > > This patch removes the MAX_FIXED_MODE_SIZE override, which fixes the error. > > > > PR target/120144 > > > > gcc/ChangeLog: > > > > * config/mips/mips.h (MAX_FIXED_MODE_SIZE): Remove. > > This introduces an ICE building libstdc++ for mips64-linux-gnu > (preprocessed source attached, not reduced). > > Note 1: there is a similar ICE also on GCC mainline, but only for certain > little-endian configurations, whereas with GCC 15 branch I see this for a > wider range of MIPS configurations used by build-many-glibcs.py, both BE > and LE. I'm not sure exactly when the ICE appeared on GCC mainline (the > build of glibc in my bot using GCC mainline was broken for a while because > of -Wconstant-logical-operand issues in glibc), but it wasn't introduced > by the commit being backported; it appeared some time later, so maybe > there is an interaction of multiple commits involved. > > Note 2: I haven't tested for this issue with GCC 16 branch.
Having now tested with GCC 16 branch, I don't see the issue there (that is, I don't see any failures to build libstdc++ for MIPS configurations in build-many-glibcs.py with GCC 16 branch). Though it seems likely the underlying issue is present on GCC 16 branch as well as on GCC mainline and having been introduced to GCC 15 branch by the backport, even if latent on GCC 16 branch for the particular test of building libstdc++. -- Joseph S. Myers [email protected]
