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[Bug middle-end/40106] [4.4/4.5 Regression] Weird interaction between optimize_insn_for_speed_p and -funsafe-math-optimizations
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 16 Mar 2010 15:26:06 -0000
- Subject: [Bug middle-end/40106] [4.4/4.5 Regression] Weird interaction between optimize_insn_for_speed_p and -funsafe-math-optimizations
- References: <bug-40106-12313@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #38 from rguenth at gcc dot gnu dot org 2010-03-16 15:26 -------
Btw, the testcase has
D.1610_34 = __builtin_pow (D.1564_28, 1.5e+0);
which would expand to
D.1564_28 * sqrt (D.1564_28)
which is estimated as being larger than the call to pow. Now this isn't
exactly
true if the target has a sqrt insn, but we do not implement such a
sophisticated
size check.
Especially on embedded targets with soft-float the multiplication would
add a significant code size penalty.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40106