[Bug middle-end/50913] [4.7 Regression] ICE in scan_tree_for_params_right_scev, at graphite-sese-to-poly.c:633 compiling libgfortran with -floop-interchange -m32

[matt at use dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50913

Matt Hargett <matt at use dot net> changed:

           What    |Removed                     |Added
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                 CC|                            |matt at use dot net

--- Comment #6 from Matt Hargett <matt at use dot net> 2011-12-10 03:23:51 UTC ---
I ran into this as well when compiling scummvm with "-O2 -floop-block". I can't
tell, but it may be a regression of PR42930. I filed a new bug as PR51943. If
this bug turns out to be a duplicate of PR51943, let me know and I'll add the
relevant info to this bug.

One way to tell is if you see this approximate valgrind output when reproducing
your testcase:

==21219== Conditional jump or move depends on uninitialised value(s)
==21219==    at 0xD02445: refs_may_alias_p_1(ao_ref_s*, ao_ref_s*, bool)
(tree-ssa-alias.c:1027)
==21219==    by 0xA92139: stmt_may_clobber_ref_p_1(gimple_statement_d*,
ao_ref_s*) (tree-ssa-alias.c:1762)
==21219==    by 0xA92210:
_ZL20walk_aliased_vdefs_1P8ao_ref_sP9tree_nodePFbS0_S2_PvES3_PP15bitmap_head_defj.955263.constprop.2845.16875
(tree-ssa-alias.c:2158)
==21219==    by 0xA9238D: walk_aliased_vdefs(ao_ref_s*, tree_node*, bool
(*)(ao_ref_s*, tree_node*, void*), void*, bitmap_head_def**)
(tree-ssa-alias.c:2178)
==21219==    by 0xA9335E:
_ZL20detect_type_change_1P9tree_nodeS0_S0_P18gimple_statement_dP13ipa_jump_funcl.498561.15992
(ipa-prop.c:460)
==21219==    by 0xA9634B: ipa_analyze_node(cgraph_node*) (ipa-prop.c:1505)
==21219==    by 0xA96F88: _ZL21ipcp_generate_summaryv.1445752 (ipa-cp.c:2490)
==21219==    by 0xE3AF25: execute_ipa_summary_passes(ipa_opt_pass_d*)
(passes.c:1888)
==21219==    by 0x9912C6: cgraph_optimize() (cgraphunit.c:2059)
==21219==    by 0x991559: cgraph_finalize_compilation_unit()
(cgraphunit.c:1327)
==21219==    by 0xCE3EBA: cp_write_global_declarations() (decl2.c:4050)
==21219==    by 0xC8DA2F: toplev_main(int, char**) (toplev.c:573)
==21219==  Uninitialised value was created by a stack allocation
==21219==    at 0xA934ED:
_ZL22detect_type_change_ssaP9tree_nodeP18gimple_statement_dP13ipa_jump_func.498569.15987
(ipa-prop.c:511)