RTS build failure with gcc-4.6.1

[erikd]

Building ghc from git HEAD on x86_64-linux (Debian unstable) with gcc-4.6 and getting:

"inplace/bin/ghc-stage1" -optc-Wall -optc-Werror -optc-Wall -optc-Wextra -optc-Wstrict-prototypes -optc-Wmissing-prototypes -optc-Wmissing-declarations -optc-Winline -optc-Waggregate-return -optc-Wpointer-arith -optc-Wmissing-noreturn -optc-Wnested-externs -optc-Wredundant-decls -optc-Iincludes -optc-Irts -optc-DCOMPILING_RTS -optc-fno-strict-aliasing -optc-fno-common -optc-Ilibffi/build/include -optc-fomit-frame-pointer -optc-DRtsWay=\"rts_thr\" -optc-DTHREADED_RTS  -H32m -O -Wall -Werror -H64m -O0 -Iincludes -Irts -DCOMPILING_RTS -package-name rts  -dcmm-lint  -Ilibffi/build/include     -i -irts -irts/dist/build -irts/dist/build/autogen -Irts/dist/build -Irts/dist/build/autogen           -optc-O2   -c rts/Capability.c -o rts/dist/build/Capability.thr_o
rts/Capability.c: In function 'releaseCapability_':

rts/Capability.c:341:1:
     error: inlining failed in call to 'giveCapabilityToTask.isra.12.part.13': call is unlikely and code size would grow [-Werror=inline]

rts/Capability.c:368:1:  error: called from here [-Werror=inline]

rts/Capability.c:341:1:
     error: inlining failed in call to 'giveCapabilityToTask.isra.12.part.13': call is unlikely and code size would grow [-Werror=inline]

rts/Capability.c:368:1:  error: called from here [-Werror=inline]

rts/Capability.c:341:1:
     error: inlining failed in call to 'giveCapabilityToTask.isra.12.part.13': call is unlikely and code size would grow [-Werror=inline]

rts/Capability.c:368:1:  error: called from here [-Werror=inline]
cc1: all warnings being treated as errors

make[1]: *** [rts/dist/build/Capability.thr_o] Error 1

[dterei]

So I've added a patch that fixes the validation errors. Unfortunately it causes a bug where the stage2 compiler freezes when compiling the utils/ghctags/Main.hs file.

[igloo@…]

commit 0a6f26f6d29c8762b254e2f1040fce5c3571feea Author: Ian Lynagh <igloo@…> Date: Fri Jun 24 20:51:13 2011 +0100

Fix gcc 4.6 warnings; fixes #5176

Based on a patch from David Terei.

Some parts are a little ugly (e.g. defining things that only ASSERTs use only when DEBUG is defined), so we might want to tweak things a little.

I've also turned off -Werror for didn't-inline warnings, as we now get a few such warnings.

[igloo]

Fixed