[Bug rtl-optimization/85376] [8 Regression] wrong code with -Og -fno-dce -fgcse -fno-tree-ccp -fno-tree-copy-prop

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85376

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
-fdisable-rtl-cprop2 -fdisable-rtl-cprop1 fixes it, likewise
-fdisable-rtl-cse_local:

> diff -u t.c.245r.cprop2 t.c.247r.cse_local
...
-   41: r194:SI=0x20
-      REG_DEAD r91:HI
    42: r108:QI=0
-   43: {flags:CC=cmp(r194:SI#0,r104:SI#0);r195:QI=r194:SI#0-r104:SI#0;}
+   43: {flags:CC=cmp(r93:SI#0,r104:SI#0);r195:QI=r93:SI#0-r104:SI#0;}

huh.