On Tue, Mar 20, 2018 at 3:08 AM, Richard Biener <rguent...@suse.de> wrote: > > With the x86 vectorizer cost-model rewrite we ended up costing > scalar conversions as nothing. After my patch using the proper > target cost estimates for the scalar version this now exposes > underestimating scalar cost and thus no longer vectorizing > the testcase in this PR. This fix is to restrict zero-costing > to sign-conversions, all other conversions are possibly > value-changing. I guess some zero-extensions are free as well > but I didn't want to get too fancy as I'm not sure about > QImode -> SImode conversions for example since whether > that's free (can just use %eax instead of %ax) likely depends on > context. > > Bootstrap and regtest running on x86_64-unknown-linux-gnu. > > OK? > > Thanks, > Richard. > > 2018-03-20 Richard Biener <rguent...@suse.de> > > PR target/84986 > * config/i386/i386.c (ix86_add_stmt_cost): Only cost > sign-conversions as zero, fall back to standard scalar_stmt > cost for the rest. > > * gcc.dg/vect/costmodel/x86_64/costmodel-pr84986.c: New testcase. >
The test failed for -mx32: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85066 -- H.J.
