slp pass assert when compiler configure with --enable-checking

[mickael guene]

When compiling attached small.c file with linaro-4.6-2012.03 configured with --enable-checking and gcc options :
gcc -c small.c -msoft-float -march=armv7-a -mfloat-abi=softfp -mfpu=neon -mvectorize-with-neon-quad -ftree-vectorize -O2

I have a great number of assertion due to access to unallocated memory.
patch from Bug #960274 plus attached patch fix them all (certainly badly)

I have not done a very deep analysis but either analysis pass make a wrong decision when applying slp optimization or
code is seriously bugged.

[Ulrich Weigand (uweigand)]

Thanks for the bug report. I can confirm this also with current mainline. I'll have a look.

[Ulrich Weigand (uweigand)]

It seems the root cause of all the memory problems is that vect_get_smallest_scalar_type neglected to handle WIDEN_LSHIFT_EXPR, which causes the SLP pass to mis-compute the number of statements needed to vectorize the expression. The attached patch (together with your patch from #960274) fixes the ICEs for me ...

[mickael guene (mickael-guene)]

  I have test patch from #960274 + your patch and now it works well.
 Thanks for the fix

[Ulrich Weigand (uweigand)]

Opened upstream bug:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52686

[Ulrich Weigand (uweigand)]

Fix committed to mainline, Linaro GCC 4.6, and Linaro GCC 4.7.