http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49602
Summary: verify_ssa failed (definition does not dominate use) with "-O2 -g" Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassig...@gcc.gnu.org ReportedBy: arthur.j.odw...@gmail.com Created attachment 24649 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24649 Output of "ajo-gcc -std=c99 -O2 -g -w -c test.c -v" This failure reproduces for me with svn revision 175547 (2011-06-27). I've seen it twice in random testing, and never saw it back in May, so it must be a fairly new regression. I'm on Ubuntu 10.10, x86-64. cat >test.c <<EOF static void use(int *p_29) { } void func_25(int *p_29) { for (short p_26 = 0; p_26 == 1; ++p_26) p_29 = 0; use(p_29); } EOF gcc -std=c99 -O2 -g -w -c test.c test.c: In function ‘func_25’: test.c:6:1: error: definition in block 3 does not dominate use in block 5 for SSA_NAME: p_29_3 in statement: # DEBUG D#1 => p_29_3 test.c:6:1: internal compiler error: verify_ssa failed Bug 40711 (from 2009) has the same symptom, but doesn't require "-g", so it probably has a different root cause. This test case is reduced from the output of Csmith 2.1.0 (git hash 01aa8b04, https://github.com/Quuxplusone/csmith/), using the following command line: csmith --no-paranoid --longlong --pointers --no-arrays --jumps --no-consts --volatiles --checksum --no-divs --muls --no-bitfields --no-packed-struct -s 651222746