https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104263
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |10.4 Ever confirmed|0 |1 Last reconfirmed| |2022-01-28 Priority|P3 |P2 Status|UNCONFIRMED |NEW --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed. Caused by store-merging: -Coalescing successful! -Merged into 1 stores -New sequence of 1 stores to replace old one of 2 stores -Merging successful! __attribute__((returns_twice, pure)) int foo () { <bb 2> [local count: 1073741824]: + # DEBUG BEGIN_STMT + # DEBUG INLINE_ENTRY bar + # DEBUG BEGIN_STMT + # DEBUG BEGIN_STMT + n = 0; + # DEBUG BEGIN_STMT + # DEBUG a => 0 + # DEBUG BEGIN_STMT <bb 3> [local count: 1073312329]: - MEM[(int *)&n] = 1; + n = 1; + # DEBUG BEGIN_STMT <bb 4> [local count: 1073741824]: + # DEBUG BEGIN_STMT return 0; <bb 5> [local count: 429496]: so we fail to merge n = 0 and n = 1 with -g.