[RFC] failures found while pounding on GCC trunk

[Janis Johnson <janis187 at us dot ibm dot com>]

In http://gcc.gnu.org/ml/gcc-patches/2007-09/msg01702.html I describe
tools to generate sets of GCC command-line options used to find
combinations that don't work together.  Using those tools and a setup
to build and run (with short test input) individual tests from SPEC
CPU2000, I've found the following 7 wrong-code failures and 15
ice-on-valid-code failures on powerpc64-linux.  A few of them have
several options, but many are just a single change from -O2 or -Os.

Before I start minimizing test cases and filing bugs I'd like some
feedback about failures that aren't likely to be investigated so I
can ignore those for now.  There might be combinations that we'd want
to disallow.

#######################################################################
# Failures in SPEC CPU2000 tests on powerpc64-linux found by using
# command lines generated by GENOPTS.

#----------------------------------------------------------------------
# Run/miscompare failures (wrong-code)
#----------------------------------------------------------------------

# gcc, perlbmk run fails; -m32
-O2 -ftrapv
-Os -ftrapv

# perlbmk run fails; -m32
# (documented as experimental)
-O2 -fsched2-use-superblocks

# perlbmk run fails; -m32
-O2 -fno-trapping-math
-Os -fno-trapping-math

# perlbmk run fails; -m32
-Os -funroll-all-loops

# perlbmk run fails; -m32
-Os -funroll-loops -fno-tree-copyrename -fno-tree-dce

# gap, gcc, vortex run fails; -m64
-fpack-struct

# perlbmk run fails; -m64
-Os -fno-forward-propagate -fforce-addr -fpack-struct

#----------------------------------------------------------------------
# Build failures (mostly ice-on-valid-code)
#----------------------------------------------------------------------

# all tests fail with unrecognizable insn, segfault; -m32/-m64
-O2 -frtl-abstract-sequences
-Os -frtl-abstract-sequences

# all tests fail with ICE in verify_ssa; -m32/-m64
-O2 -fipa-pta
-Os -fipa-pta

# all tests fail with ICE in verify_curr_properties; -m32/-m64
-O2 -fno-tree-salias
-Os -fno-tree-salias

# all tests fail with ICE in verify_curr_properties; -m32/-m64
# (-ftree-scev-cprop is not documented)
-O2 -fno-tree-ch -fno-tree-scev-cprop

# almost all tests fail with ICE in verify_flow_info; m32/-m64
-O2 -fmodulo-sched -freorder-blocks-and-partition
-Os -fmodulo-sched -freorder-blocks-and-partition

# almost all tests fail with vector VEC index domain error; -m32/-m64
-O2 -fno-tree-ch -fno-tree-copy-prop -fno-tree-dominator-opts -fno-tree-store-copy-prop -fno-tree-vrp

# ten tests fail with missing barrier after block with -O2; -m64
# fourteen tests fail with missing barrier after block with -Os; -m64
# (documented as experimental)
# failures might be somewhat intermittent
-O2 -fsched2-use-superblocks
-Os -fsched2-use-superblocks

# mesa fails with invalid rtl sharing; -m64
-O2 -fno-trapping-math
-Os -fno-trapping-math

# crafty fails with ICE in local_cprop_pass; -m32/-m64
-O2 -ftrapv
-Os -ftrapv

# crafty, vortex fail with multiple or missing defs; -m32/-m64
-O2 -fno-unit-at-a-time

# gcc fails with ICE in verify_flow_info; -m32
-Os -fno-forward-propagate -fno-guess-branch-probability -fno-move-loop-invariants -fno-tree-dominator-opts -fno-tree-loop-optimize

# gcc fails with missing defs; -m32
-Os -fno-unit-at-a-time

# gzip fails with ICE in build_polynomial_chrec; -m32/-m64
-Os -fno-tree-ch -fno-tree-scev-cprop

# ammp, gap, gcc, perlbmk, twolf, vortex fail with ICE in
# vrp_evaluate_conditional_warnv; -m32/-m64
-Os -fno-tree-copy-prop -fno-tree-dce -fipa-cp

# twolf fails with ICE (segfault); -m64
-Os -fsched-stalled-insns

# eon build fails with (valid?) error; -m32/-m64
-fpack-struct
#----------------------------------------------------------------------

Janis