[llvm] [LV] Don't predicate divs with invariant divisor when folding tail (PR #98904)

[via llvm-commits]

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@@ -207,25 +207,8 @@ define i32 @sink_replicate_region_3_reduction(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule vp<[[WIDEN_CAN]]>, vp<[[BTC]]>
 ; CHECK-NEXT:   WIDEN-CAST ir<%recur.next> = sext ir<%y> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT: Successor(s): pred.srem
-; CHECK-EMPTY:
-; CHECK-NEXT: <xVFxUF> pred.srem: {
-; CHECK-NEXT:   pred.srem.entry:
-; CHECK-NEXT:     BRANCH-ON-MASK vp<[[MASK]]>
-; CHECK-NEXT:   Successor(s): pred.srem.if, pred.srem.continue
-; CHECK-EMPTY:
-; CHECK-NEXT:   pred.srem.if:
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
-; CHECK-NEXT:   Successor(s): pred.srem.continue
-; CHECK-EMPTY:
-; CHECK-NEXT:   pred.srem.continue:
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<[[PRED:%.+]]> = ir<%rem>
-; CHECK-NEXT:   No successors
-; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.0
-; CHECK-EMPTY:
-; CHECK-NEXT: loop.0:
-; CHECK-NEXT:   WIDEN ir<%add> = add vp<[[PRED]]>, ir<%recur.next>
+; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
+; CHECK-NEXT:   WIDEN ir<%add> = add ir<%rem>, ir<%recur.next>
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ayalz wrote:

Note: srem in header with invariant divisor gets widened w/o mask rather than scalarized and predicated.

https://github.com/llvm/llvm-project/pull/98904