https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86659
--- Comment #1 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot
Uni-Bielefeld.DE> ---
A reghunt now identified this patch as the culprit:
2018-07-24 Richard Biener <rguent...@suse.de>
* match.pd: Add BIT_FIELD_REF canonicalizations.
Comparing the assembler output, I find
--- /var/gcc/reghunt/pr86659/47386/gcc/testsuite/gnat/q2.s 2018-07-25
13:27:50.135854630 +0000
+++ q2.s 2018-07-25 13:28:06.147647885 +0000
@@ -309,10 +309,7 @@
call __gnat_rcheck_PE_Explicit_Raise, 0
nop
.LL2:
- ldx [%fp+2039], %o0
- call __bswapdi2, 0
- nop
- mov %o0, %g1
+ ldx [%fp+2039], %g1
and %g1, 3, %g1
cmp %g1, 2
be %xcc, .LL3
