http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57223
Usishchev Yury <y.usishchev at samsung dot com> changed:
What |Removed |Added
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CC| |y.usishchev at samsung dot com
--- Comment #3 from Usishchev Yury <y.usishchev at samsung dot com> ---
I'm testing it on current trunk, and second loop is not vectorized both with
floating point and integer types.
For floating point types it is not vectorized due to control flow in loop:
<bb 15>:
// ...
if (t_56 > _61)
goto <bb 16>;
else
goto <bb 17>;
<bb 16>:
<bb 17>:
# iftmp.2_7 = PHI <_61(16), t_56(15)>
This can be optimized to MIN_EXPR in phiopt pass, but is not because of NaNs:
tree-ssa-phiopt.c:876:
/* The optimization may be unsafe due to NaNs. */
if (HONOR_NANS (TYPE_MODE (type)))
return false;
If compiled with -ffinite-math-only second loop still is not vectorised:
not_always_good.c:16:7: note: not vectorized: latch block not empty.
(same occurs with integer types). Latch block it that case is:
<bb 14>:
pretmp_176 = *prephitmp_173;
goto <bb 13>;
the statement here is generated in pre pass.
For vectorization to work we can either not generate it in pre or move it into
head of the loop in vectorizer.
Right now i'm trying to find how to prevent pre from generating statements in
empty latch blocks.
