[LLVMdev] 32bit math being promoted to 64 bit

[Villmow, Micah]

instcombine doesn't seem to be doing it. From my testing it seems to
only occur when I use -indvars after a long string of commands.

For example:
llvm-as < test_fc_27.ll | opt    -preverify  -domtree  -verify
-lowersetjmp  -raiseallocs  -simplifycfg  -domtree  -domfrontier
-mem2reg  -globalopt  -globaldce  -ipconstprop  -deadargelim
-instcombine  -simplifycfg  -ba
siccg  -prune-eh  -inline  -argpromotion  -simplify-libcalls
-instcombine  -jump-threading  -simplifycfg  -domtree  -domfrontier
-scalarrepl  -instcombine  -break-crit-edges  -condprop  -tailcallelim
-simplifycfg  -reassociate  -domtree -loops  -loopsimplify  -domfrontier
-scalar-evolution  -lcssa  -loop-rotate  -licm  -lcssa
-scalar-evolution  -lcssa  -loop-index-split  -instcombine
-scalar-evolution  -lcssa   -simplifycfg -view-cfg 

Doesn't cause it, but 
llvm-as < test_fc_27.ll | opt    -preverify  -domtree  -verify
-lowersetjmp  -raiseallocs  -simplifycfg  -domtree  -domfrontier
-mem2reg  -globalopt  -globaldce  -ipconstprop  -deadargelim
-instcombine  -simplifycfg  -ba
siccg  -prune-eh  -inline  -argpromotion  -simplify-libcalls
-instcombine  -jump-threading  -simplifycfg  -domtree  -domfrontier
-scalarrepl  -instcombine  -break-crit-edges  -condprop  -tailcallelim
-simplifycfg  -reassociate  -domtree -loops  -loopsimplify  -domfrontier
-scalar-evolution  -lcssa  -loop-rotate  -licm  -lcssa
-scalar-evolution  -lcssa  -loop-index-split  -instcombine
-scalar-evolution  -lcssa -indvars -simplifycfg -view-cfg

does.

However, opt -indvars does not cause it, so it seems to be a sequence of
operations that is causing it and not -indvars by itself.

Hope this helps,
Micah
-----Original Message-----
From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
On Behalf Of Tilmann Scheller
Sent: Thursday, December 04, 2008 10:28 AM
To: LLVM Developers Mailing List
Subject: Re: [LLVMdev] 32bit math being promoted to 64 bit

On Thu, Dec 4, 2008 at 7:08 PM, Chris Lattner <clattner at apple.com>
wrote:
>
> On Dec 4, 2008, at 8:58 AM, Villmow, Micah wrote:
>
> What optimization pass promotes 32 bit math operations to 64 bit
operations
> so I can disable it? I have code that works fine with optimizations
turned
> off but fails with it turned on because of this stage.
>
>
> Do you have a testcase?  An .ll file with no 64-bit operations, and
one
> optimization pass that introduces them?

Sounds a lot like the issue I reported in PR 3101.

Can you run your bitcode through opt -instcombine and check for
promotions?

Greetings,

Tilmann
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