[LLVMdev] 32bit math being promoted to 64 bit

[Scott Michel]

This wouldn't normally be a problem. But it's ironic that this  
instcombine feature is happening in the middle of libgcc's 64-bit  
multiplication emulation code.

To get 64-bit multiplication for the Cell SPU, you have to compile  
__muldi3.c, into which instcombine inserts 64-bit multiplication.


-scooter

On Dec 4, 2008, at 10:53 AM, Anton Korobeynikov wrote:

>> Do you have a testcase?  An .ll file with no 64-bit operations,  
>> and one
>> optimization pass that introduces them?
> It's pretty common to instcombine to expand 32 bit operations to 64
> bit. See, for example, recent issue with CellSPU's 32 =>64 bit muls
>
> -- 
> With best regards, Anton Korobeynikov
> Faculty of Mathematics and Mechanics, Saint Petersburg State  
> University
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