[Bug tree-optimization/24123] [4.1 Regression] Massive performance regression for -ffast-math due to the recip tree pass

[paolo dot bonzini at lu dot unisi dot ch]

------- Additional Comments From paolo dot bonzini at lu dot unisi dot ch  2005-09-30 14:40 -------
Subject: Re:  [4.1 Regression] Massive performance
 regression for -ffast-math due to the recip tree pass


>>>Function double pov::POVFPU_RunDefault(pov::FUNCTION)
>>>
>>><L193>:;
>>>-  r0_1660 = r0_89 / r0_89;
>>>+  reciptmp.492_84 = 1.0e+0 / r0_89;
>>>+  r0_1660 = r0_89 * reciptmp.492_84;
>>>  goto <bb 1062> (<L1339>);
>>>
>>>The result of above confusion is (1.0)! We are in fast-math, so no NaNs, etc..
>>>      
>>>
Can you prepare a patch to fold, that fixes this beauty? :-)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24123