http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53461
Bug #: 53461
Summary: Incorrect handling of CASE_VECTOR_PC_RELATIVE in
config/m68k.md
Classification: Unclassified
Product: gcc
Version: 4.6.3
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: gvvn1...@gmail.com
I have been trying to port a recent gcc version to m68k-next-nextstep3 target
and encountered an ICE in the stage1 compiler. With help of the m68k debian
ports community I was able to identify a bug in config/m68k/m68k.md. This bug
exists in all reasonably recent versions of gcc but not in gcc-3.2 and gcc-3.4.
The m68k.md file contains the following conditional statement:
#ifdef CASE_VECTOR_PC_RELATIVE
operands[0] = gen_rtx_PLUS (SImode, pc_rtx,
gen_rtx_SIGN_EXTEND (SImode, operands[0]));
#endif
If the target configuration files undefine CASE_VECTOR_PC_RELATIVE, the
defaults.h header redefines CASE_VECTOR_PC_RELATIVE as follows:
/* Assume that case vectors are not pc-relative. */
#ifndef CASE_VECTOR_PC_RELATIVE
#define CASE_VECTOR_PC_RELATIVE 0
#endif
The defaults.h header file is included after the target configuration files and
thus overrides the CASE_VECTOR_PC_RELATIVE. The conditional statement in
config/m68k/m68k.md is therefore always satisfied even if the target
configuration undefines CASE_VECTOR_PC_RELATIVE.
I was able to resolve the issue with the following change to
config/m68k/m68k.md:
#if CASE_VECTOR_PC_RELATIVE != 0
operands[0] = gen_rtx_PLUS (SImode, pc_rtx,
gen_rtx_SIGN_EXTEND (SImode, operands[0]));
#endif
t-rexky
