[Polly][PATCH 4/8] Allow the IslExprBuilder to compare pointers

[Johannes Doerfert]

Attached a new version, as compact as it gets.

On 08/11, Johannes Doerfert wrote:
> On 08/11, Tobias Grosser wrote:
> > On 11/08/2014 10:56, Johannes Doerfert wrote:
> > >On 08/11, Tobias Grosser wrote:
> > >>On 11/08/2014 09:38, Johannes Doerfert wrote:
> > >>>On 08/11, Tobias Grosser wrote:
> > >>>>Please merge this into the patch that actually tests and uses it.
> > >>>>
> > >>>>Some comments inline:
> > >>>>
> > >>>>On 10/08/2014 09:50, Johannes Doerfert wrote:
> > >>>>[..]
> > >>>>>    switch (isl_ast_expr_get_op_type(Expr)) {
> > >>>>>    default:
> > >>>>>@@ -280,16 +286,20 @@ Value *IslExprBuilder::createOpICmp(__isl_take isl_ast_expr *Expr) {
> > >>>>>      Res = Builder.CreateICmpEQ(LHS, RHS);
> > >>>>>      break;
> > >>>>>    case isl_ast_op_le:
> > >>>>>-    Res = Builder.CreateICmpSLE(LHS, RHS);
> > >>>>>+    Res = IsPtrType ? Builder.CreateICmpULE(LHS, RHS)
> > >>>>>+                    : Builder.CreateICmpSLE(LHS, RHS);
> > >>>>>      break;
> > >>>>>    case isl_ast_op_lt:
> > >>>>>-    Res = Builder.CreateICmpSLT(LHS, RHS);
> > >>>>>+    Res = IsPtrType ? Builder.CreateICmpULT(LHS, RHS)
> > >>>>>+                    : Builder.CreateICmpSLT(LHS, RHS);
> > >>>>>      break;
> > >>>>>    case isl_ast_op_ge:
> > >>>>>-    Res = Builder.CreateICmpSGE(LHS, RHS);
> > >>>>>+    Res = IsPtrType ? Builder.CreateICmpUGE(LHS, RHS)
> > >>>>>+                    : Builder.CreateICmpSGE(LHS, RHS);
> > >>>>>      break;
> > >>>>>    case isl_ast_op_gt:
> > >>>>>-    Res = Builder.CreateICmpSGT(LHS, RHS);
> > >>>>>+    Res = IsPtrType ? Builder.CreateICmpUGT(LHS, RHS)
> > >>>>>+                    : Builder.CreateICmpSGT(LHS, RHS);
> > >>>>
> > >>>>Did you consider CreateICmp(Predicate, LHS, RHS), plus a table that
> > >>>>maps the enum values to the corresponding predicates? This code seems
> > >>>>to start to have a lot of duplication.
> > >>>I did not really, but we could use a two dimensional table if you prefer that.
> > >>
> > >>Does a 2D table work? I think we would need a map for this, as the index is
> > >>an enum, no?
> > >Yes, isl enums = C enums = int
> > >
> > >>Otherwise, we could just make this two switch statements, that select
> > >>the ICmp predicate and than just have a single call to Builder.CreateImp at
> > >>the end. What do you think?
> > >I don't have any strong feeling about it, or in other words I think
> > >that's a lot of discussion about 10 lines of code which just builds a
> > >compare instruction.
> > >
> > >Tell me what you want and I change it to whatever.
> > 
> > I would pull out the Builder.Create* from the switch statement and instead
> > just select the predicate.
> > 
> > We can then use Builder.CreateICmp(Predicate, LHS, RHS) after the switch.
> That answers only a quarter of the questions. You mentioned a table
> (which I interpreted as a 2D table), a map and "two switch statements"
> in order to select the right Predicate (which is the actuall challenge here).
> 
> What is it going to be?
> 
> > 
> > Cheers,
> > Tobias
> 
> -- 
> 
> Johannes Doerfert
> Researcher / PhD Student
> 
> Compiler Design Lab (Prof. Hack)
> Saarland University, Computer Science
> Building E1.3, Room 4.26
> 
> Tel. +49 (0)681 302-57521 : doerfert at cs.uni-saarland.de
> Fax. +49 (0)681 302-3065  : http://www.cdl.uni-saarland.de/people/doerfert



> _______________________________________________
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-- 

Johannes Doerfert
Researcher / PhD Student

Compiler Design Lab (Prof. Hack)
Saarland University, Computer Science
Building E1.3, Room 4.26

Tel. +49 (0)681 302-57521 : doerfert at cs.uni-saarland.de
Fax. +49 (0)681 302-3065  : http://www.cdl.uni-saarland.de/people/doerfert
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