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[Bug middle-end/77568] [7 regression] CSE/PRE/Hoisting blocks common instruction contractions
- From: "pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 13 Sep 2016 13:46:59 +0000
- Subject: [Bug middle-end/77568] [7 regression] CSE/PRE/Hoisting blocks common instruction contractions
- Auto-submitted: auto-generated
- References: <bug-77568-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77568
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |FIXME
--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The code in tree-ssa-math-opts.c has the following comment in it:
/* For now restrict this operations to single basic blocks. In theory
we would want to support sinking the multiplication in
m = a*b;
if ()
ma = m + c;
else
d = m;
to form a fma in the then block and sink the multiplication to the
else block. */
if (gimple_bb (use_stmt) != gimple_bb (mul_stmt))
return false;