https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110777
Bug ID: 110777 Summary: ice: SSA corruption Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: dcb314 at hotmail dot com Target Milestone: --- This C code int *findOrAddBackgroundInPalette_palette_pnm; static void findOrAddBackgroundInPalette(unsigned *paletteSizeP, int *backgroundIndexP) { if (*paletteSizeP) { *backgroundIndexP = (*paletteSizeP)++; pm_message(); } pm_message(findOrAddBackgroundInPalette_palette_pnm[*backgroundIndexP]); } void computeColorMap(int *backgroundIndexP) { unsigned paletteSize; findOrAddBackgroundInPalette(&paletteSize, backgroundIndexP); } int main() { unsigned backgroundIndex; _setjmp(); computeColorMap(&backgroundIndex); } with recent gcc trunk, does this: $ ~/gcc/results/bin/gcc -c -O3 -w ~/cvise/bug944.c Unable to coalesce ssa_names 27 and 31 which are marked as MUST COALESCE. paletteSize_27(ab) and paletteSize_31(ab) during RTL pass: expand /home/dcb38/cvise/bug944.c: In function ‘main’: /home/dcb38/cvise/bug944.c:14:5: internal compiler error: SSA corruption 14 | int main() { | ^~~~ 0xf95b19 fail_abnormal_edge_coalesce(int, int) ../../trunk.year/gcc/tree-ssa-coalesce.cc:1003 0xf95b19 coalesce_partitions(_var_map*, ssa_conflicts*, coalesce_list*, _IO_FILE*) ../../trunk.year/gcc/tree-ssa-coalesce.cc:1425 The bug first seems to occur sometime between g:b2cfe5233e682fc0 and g:f32518726ee8e836, a range of 30 commits.