[PATCH] Use ScalarEvolution to create tight bounds on the parameters

[Sebastian Pop]

On Thu, Feb 12, 2015 at 2:03 AM, Johannes Doerfert
<doerfert at cs.uni-saarland.de> wrote:
> Index: test/ScopInfo/ranged_parameter.ll
> ===================================================================
> --- /dev/null
> +++ test/ScopInfo/ranged_parameter.ll
> @@ -0,0 +1,38 @@
> +; RUN: opt %loadPolly -polly-scops -analyze < %s | FileCheck %s
> +;
> +; CHECK: Context:
> +; CHECK:   [p_0] -> {  : p_0 >= 0 and p_0 <= 255 }
> +;
> +;    void jd(int *A, int *p /* in [0,256) */) {

I don't see A statically defined, so we don't know its size, and so I wonder
what information do we look at to compute that *p is in [0,256)?

> +;      for (int i = 0; i < 1024; i++)
> +;        A[i + *p] = i;
> +;    }
> +;
> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> +
> +define void @jd(i32* %A, i32* %p) {
> +entry:
> +  %tmp = load i32* %p, align 4, !range !0
> +  br label %for.cond
> +
> +for.cond:                                         ; preds = %for.inc, %entry
> +  %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
> +  %exitcond = icmp ne i32 %i.0, 1024
> +  br i1 %exitcond, label %for.body, label %for.end
> +
> +for.body:                                         ; preds = %for.cond
> +  %add = add i32 %i.0, %tmp
> +  %idxprom = sext i32 %add to i64
> +  %arrayidx = getelementptr inbounds i32* %A, i64 %idxprom
> +  store i32 %i.0, i32* %arrayidx, align 4
> +  br label %for.inc
> +
> +for.inc:                                          ; preds = %for.body
> +  %inc = add nsw i32 %i.0, 1
> +  br label %for.cond
> +
> +for.end:                                          ; preds = %for.cond
> +  ret void
> +}
> +
> +!0 =  !{ i32 0, i32 256 }
>
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