[llvm] [loop-vectorize] Fix crash when using types that aren't known scale factors (PR #136680)

[Nicholas Guy via llvm-commits]

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@@ -1030,6 +1030,27 @@ for.body:                                         ; preds = %for.body.preheader,
   br i1 %exitcond.not, label %for.cond.cleanup, label %for.body, !loop !1
 }
 
+
+define i40 @chained_partial_reduce_not_known_factor(i32 %a, i32 %b, i32 %N) {
+entry:
+  br label %for.body
+
+for.body:
+  %red = phi i40 [ 0, %entry ], [ %1, %for.body ]
+  %iv = phi i16 [ 0, %entry ], [ %iv.next, %for.body ]
+  %resize = sext i32 %a to i40
+  %resize4 = sext i32 %b to i40
+  %0 = or i40 %resize4, %resize
+  %1 = or i40 %red, %0
+  %iv.next = add i16 %iv, 1
+  %cmp = icmp slt i16 %iv, 1
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NickGuy-Arm wrote:

It does indeed. I've made it use %N as it was otherwise unused.

https://github.com/llvm/llvm-project/pull/136680