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* [Bug tree-optimization/96714] New: Failure to optimize sqrt*sqrt of same variable with ffast-math
@ 2020-08-19 20:23 gabravier at gmail dot com
2020-08-25 11:14 ` [Bug tree-optimization/96714] " rguenth at gcc dot gnu.org
2020-08-25 12:09 ` gabravier at gmail dot com
0 siblings, 2 replies; 3+ messages in thread
From: gabravier at gmail dot com @ 2020-08-19 20:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96714
Bug ID: 96714
Summary: Failure to optimize sqrt*sqrt of same variable with
ffast-math
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
float f(float x)
{
return __builtin_sqrtf(x) * __builtin_sqrtf(x);
}
This can be optimized to `return x;` (with fast math enabled). This
transformation is done by LLVM, but not by GCC.
^ permalink raw reply [flat|nested] 3+ messages in thread* [Bug tree-optimization/96714] Failure to optimize sqrt*sqrt of same variable with ffast-math 2020-08-19 20:23 [Bug tree-optimization/96714] New: Failure to optimize sqrt*sqrt of same variable with ffast-math gabravier at gmail dot com @ 2020-08-25 11:14 ` rguenth at gcc dot gnu.org 2020-08-25 12:09 ` gabravier at gmail dot com 1 sibling, 0 replies; 3+ messages in thread From: rguenth at gcc dot gnu.org @ 2020-08-25 11:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96714 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |WORKSFORME --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Huh. (if (flag_unsafe_math_optimizations) /* Simplify sqrt(x) * sqrt(x) -> x. */ (simplify (mult (SQRT_ALL@1 @0) @1) (if (!HONOR_SNANS (type)) @0)) and it works for me, with -ffast-math as you say. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/96714] Failure to optimize sqrt*sqrt of same variable with ffast-math 2020-08-19 20:23 [Bug tree-optimization/96714] New: Failure to optimize sqrt*sqrt of same variable with ffast-math gabravier at gmail dot com 2020-08-25 11:14 ` [Bug tree-optimization/96714] " rguenth at gcc dot gnu.org @ 2020-08-25 12:09 ` gabravier at gmail dot com 1 sibling, 0 replies; 3+ messages in thread From: gabravier at gmail dot com @ 2020-08-25 12:09 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96714 --- Comment #2 from Gabriel Ravier <gabravier at gmail dot com> --- Hmm, I can't reproduce it either, either I was simply wrong (on something like whether I had fast math enabled) or there is some peculiarity on my setup from 6 days ago that I missed. ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-08-25 12:09 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-08-19 20:23 [Bug tree-optimization/96714] New: Failure to optimize sqrt*sqrt of same variable with ffast-math gabravier at gmail dot com 2020-08-25 11:14 ` [Bug tree-optimization/96714] " rguenth at gcc dot gnu.org 2020-08-25 12:09 ` gabravier at gmail dot com
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