dead_or_predictable calls propagate_block without checking first if there is suddicient space in reg_n_info. That can lead to memory corruption.
Created attachment 8356 [details] proposed fix
Subject: Bug 20370 CVSROOT: /cvs/gcc Module name: gcc Branch: sh-elf-4_1-branch Changes by: amylaar@gcc.gnu.org 2005-07-18 14:57:06 Modified files: gcc : ChangeLog loop.c cse.c calls.c ifcvt.c Log message: 2005-07-15 J"orn Rennecke <joern.rennecke@st.com> cvs update -j1.531 -j1.530 loop.c Re-apply this patch: 2005-05-30 Pat Haugen <pthaugen@us.ibm.com> * loop.c (loop_invariant_p, valid_initial_value_p): Use regs_invalidated_by_call instead of call_used_regs. 2005-07-15 J"orn Rennecke <joern.rennecke@superh.com> PR rtl-optimization/18992 http://gcc.gnu.org/ml/gcc-patches/2005-07/msg01140.html Back out this patch: 2003-10-08 John David Anglin <dave.anglin@nrc-cnrc.gc.ca> PR optimization/12142 * cse.c (count_reg_usage): In a SET with a REG SET_DEST, count the uses of the register in the SET_SRC. Remove unnecessary argument. Replace it with this: * cse.c (count_reg_usage): In INSN, JUMP_INSN and CALL_INSN cases, if flag_non_call_exceptions is set and the insn may trap, pass pc_rtx as dest for recursion. In SET_SRC part of SET case, if dest is already set, pass it down unchanged. 2005-07-15 J"orn Rennecke <joern.rennecke@superh.com> PR rtl-optimization/21848 http://gcc.gnu.org/ml/gcc-patches/2005-07/msg01142.html * calls.c (emit_library_call_value_1): For const functions, add USEs of the stack slots to CALL_INSN_FUNCTION_USAGE. 2005-07-15 J"orn Rennecke <joern.rennecke@superh.com> PR rtl-optimization/20370 http://gcc.gnu.org/ml/gcc-patches/2005-07/msg01148.html * ifcvt.c (dead_or_predicable): Before calling propagate_block, call allocate_reg_info if necessary. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=sh-elf-4_1-branch&r1=2.8142.2.23&r2=2.8142.2.24 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/loop.c.diff?cvsroot=gcc&only_with_tag=sh-elf-4_1-branch&r1=1.525.2.2&r2=1.525.2.3 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cse.c.diff?cvsroot=gcc&only_with_tag=sh-elf-4_1-branch&r1=1.351.2.1&r2=1.351.2.2 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/calls.c.diff?cvsroot=gcc&only_with_tag=sh-elf-4_1-branch&r1=1.385.2.1&r2=1.385.2.2 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ifcvt.c.diff?cvsroot=gcc&only_with_tag=sh-elf-4_1-branch&r1=1.184.2.2&r2=1.184.2.3
Confirmed.
Subject: Bug 20370 CVSROOT: /cvs/gcc Module name: gcc Changes by: amylaar@gcc.gnu.org 2005-07-22 12:25:22 Modified files: gcc : ChangeLog ifcvt.c Log message: PR rtl-optimization/20370 * ifcvt.c (dead_or_predicable): Before calling propagate_block, call allocate_reg_info if necessary. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.9518&r2=2.9519 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ifcvt.c.diff?cvsroot=gcc&r1=1.193&r2=1.194
Fixed.