[llvm-commits] [llvm] r60042 - in /llvm/trunk: lib/Support/APFloat.cpp test/Transforms/IndVarsSimplify/2008-11-25-APFloatAssert.ll

[Evan Cheng]

On Nov 25, 2008, at 5:08 PM, Dale Johannesen wrote:

> On Nov 25, 2008, at 4:55 PMPST, Evan Cheng wrote:
>> On Nov 25, 2008, at 11:14 AM, Chris Lattner wrote:
>>> On Nov 25, 2008, at 11:00 AM, Evan Cheng wrote:
>>>
>>>> Author: evancheng
>>>> Date: Tue Nov 25 13:00:29 2008
>>>> New Revision: 60042
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=60042&view=rev
>>>> Log:
>>>> convertToSignExtendedInteger should return opInvalidOp instead of
>>>> asserting if sematics of float does not allow arithmetics.
>>>
>>> Are you sure?  This behavior was consistent with all the other
>>> methods.  Usually the client has to check to see if it is hacking on
>>> ppc long double and not do the optimization in question.
>>
>> The client is calling convertToInteger(). How would it know it's not
>> possible to convert ppc long double? Seems like only APFloat has this
>> information.
>
> Chris is right, it's currently caller's responsibility to check this.
> Search for PPCDoubleDouble, you'll see examples.
> isArithmeticOK is a good idea though, that's better than what it does
> now.  But many places you've only got an MVT to look at.

I've reverted this and added code to check for PPCDoubleDouble. It's  
important to keep all methods consistent. However, since these methods  
return a APFloat::opStatus, I think we should rely on that instead of  
the explicit semantics check.

Evan

>
>
>> Evan
>>
>>>
>>>
>>> -Chris
>>>
>>>>
>>>>
>>>> Added:
>>>> llvm/trunk/test/Transforms/IndVarsSimplify/2008-11-25-
>>>> APFloatAssert.ll
>>>> Modified:
>>>> llvm/trunk/lib/Support/APFloat.cpp
>>>>
>>>> Modified: llvm/trunk/lib/Support/APFloat.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=60042&r1=60041&r2=60042&view=diff
>>>>
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> = 
>>>> ===================================================================
>>>> --- llvm/trunk/lib/Support/APFloat.cpp (original)
>>>> +++ llvm/trunk/lib/Support/APFloat.cpp Tue Nov 25 13:00:29 2008
>>>> @@ -117,6 +117,11 @@
>>>>         && "Compile-time arithmetic does not support these
>>>> semantics");
>>>> }
>>>>
>>>> +  static inline bool
>>>> +  isArithmeticOk(const llvm::fltSemantics &semantics) {
>>>> +    return semantics.arithmeticOK;
>>>> +  }
>>>> +
>>>> /* Return the value of a decimal exponent of the form
>>>>   [+-]ddddddd.
>>>>
>>>> @@ -1787,7 +1792,8 @@
>>>> const integerPart *src;
>>>> unsigned int dstPartsCount, truncatedBits;
>>>>
>>>> -  assertArithmeticOK(*semantics);
>>>> +  if (!isArithmeticOk(*semantics))
>>>> +    return opInvalidOp;
>>>>
>>>> *isExact = false;
>>>>
>>>>
>>>> Added: llvm/trunk/test/Transforms/IndVarsSimplify/2008-11-25-
>>>> APFloatAssert.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarsSimplify/2008-11-25-APFloatAssert.ll?rev=60042&view=auto
>>>>
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> =
>>>> = 
>>>> ===================================================================
>>>> --- llvm/trunk/test/Transforms/IndVarsSimplify/2008-11-25-
>>>> APFloatAssert.ll (added)
>>>> +++ llvm/trunk/test/Transforms/IndVarsSimplify/2008-11-25-
>>>> APFloatAssert.ll Tue Nov 25 13:00:29 2008
>>>> @@ -0,0 +1,11 @@
>>>> +; RUN: llvm-as < %s | opt -indvars
>>>> +
>>>> +define void @t() nounwind {
>>>> +entry:
>>>> +	br label %bb23.i91
>>>> +
>>>> +bb23.i91:		; preds = %bb23.i91, %entry
>>>> +	%result.0.i89 = phi ppc_fp128
>>>> [ 0xM00000000000000000000000000000000, %entry ], [ %0,
>>>> %bb23.i91 ]		; <ppc_fp128> [#uses=2]
>>>> +	%0 = mul ppc_fp128 %result.0.i89, %result.0.i89		; <ppc_fp128>
>>>> [#uses=1]
>>>> +	br label %bb23.i91
>>>> +}
>>>>
>>>>
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