[llvm] [AArch64] Use isKnownNonZero to optimize eligible compares to cmn (PR #96349)

[David Green via llvm-commits]

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@@ -258,3 +258,34 @@ define i32 @neg_range_int(i32 %a, i32 %b, i32 %c) {
   ret i32 %retval.0
 }
 
+; (b > -3 || a < -(c | 1))
+define i32 @neg_range_int_cmn(i32 %a, i32 %b, i32 %c) {
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davemgreen wrote:

I think you can add simpler test cases that do not involve ccmp.

Are you sure this is valid to transform?

https://github.com/llvm/llvm-project/pull/96349