Hi!
This is something that has been reported privately to me.
This is in code introduced in
https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00660.html
and looks indeed like a pasto to me, before the loop there is
a very similar set of stmts without the 2 suffix, and unless
regno being a hard reg (after possible reg_renumber) implies
that regno2 (after possible reg_renumber) is a hard reg, if
unlucky we might access out of bounds.
I don't have a testcase for this, but have bootstrapped/regtested
it on x86_64-linux and i686-linux, ok for trunk?
2017-09-01 Jakub Jelinek <ja...@redhat.com>
* lra-remat.c (reg_overlap_for_remat_p): Fix a pasto.
--- gcc/lra-remat.c.jj 2017-05-25 10:37:00.000000000 +0200
+++ gcc/lra-remat.c 2017-09-01 19:42:07.615291583 +0200
@@ -684,7 +684,7 @@ reg_overlap_for_remat_p (lra_insn_reg *r
if (regno2 >= FIRST_PSEUDO_REGISTER && reg_renumber[regno2] >= 0)
regno2 = reg_renumber[regno2];
- if (regno >= FIRST_PSEUDO_REGISTER)
+ if (regno2 >= FIRST_PSEUDO_REGISTER)
nregs2 = 1;
else
nregs2 = hard_regno_nregs[regno2][reg->biggest_mode];
Jakub
