https://gcc.gnu.org/bugzilla/show_bug.cgi?id=9
--- Comment #4 from Richard Biener ---
Caused by r263290. From the log:
I'm also not sure why:
if (!first && !oprnd_info->first_pattern
/* Allow different pattern state for the defs of the
first stmt in reduction chains. */
&& (oprnd_info->first_dt != vect_reduction_def
is necessary. All that should matter is that the statements in the
node are "similar enough". It turned out to be quite hard to find a
convincing example that used a mixture of pattern and non-pattern
statements, so bb-slp-pow-1.c is the best I could come up with.
But it does show that the combination of "xi * xi" statements and
"pow (xj, 2) -> xj * xj" patterns are handled correctly.
The patch therefore just removes the whole if block.
But the build-from scalars check relied on it.
