[PATCH] D36656: [SCCP] Propagate integer range information in IPSCCP.

[Florian Hahn via Phabricator via llvm-commits]

fhahn added inline comments.


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Comment at: test/Transforms/SCCP/ip-constan-ranges.ll:89
+  %res = phi i32 [ 0, %entry], [ 1, %if.true ]
+  %call1 = tail call i32 @f3(i32 %res)
+  ret i32 %call1
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dberlin wrote:
> Is there a reason not to track ranges for variables who uses appear as arguments?
> IE start with each function call, and for the arguments, mark them so they get a bigger lattice.
> It can be done as a followup, i'm just trying to understand.
> 
I thought it would be better to be conservative to start with and using `ValueLatticeElement` as general lattice value type seemed to slightly too heavy handed. I was thinking looking into some of the suggestions made in https://bugs.llvm.org/show_bug.cgi?id=26921  to reduce the memory consumption of ValueLatticeElement.

What do you think? 


https://reviews.llvm.org/D36656