[llvm-branch-commits] [llvm] [SCEV] Prove monotonic predicates from loop entry in isKnownViaInduction (PR #231697)

[Max Kazantsev via llvm-branch-commits]

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@@ -28,17 +27,15 @@ define void @runtime_start(ptr %a, i32 %start, ptr %len.p) {
 ; CHECK-NEXT:    br label %[[LOOP:.*]]
 ; CHECK:       [[LOOP]]:
 ; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[TMP0]], %[[LOOP_PREHEADER]] ], [ [[INDVARS_IV_NEXT:%.*]], %[[LOOP]] ]
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc nuw i64 [[INDVARS_IV]] to i32
-; CHECK-NEXT:    [[IDX:%.*]] = add nsw i32 [[TMP1]], -32
-; CHECK-NEXT:    [[IDX_EXT:%.*]] = zext nneg i32 [[IDX]] to i64
+; CHECK-NEXT:    [[IDX_EXT:%.*]] = add nsw i64 [[INDVARS_IV]], -32
 ; CHECK-NEXT:    [[SRC:%.*]] = getelementptr inbounds nuw i8, ptr [[A]], i64 [[IDX_EXT]]
 ; CHECK-NEXT:    [[V:%.*]] = load i8, ptr [[SRC]], align 1
 ; CHECK-NEXT:    [[V1:%.*]] = add i8 [[V]], 1
 ; CHECK-NEXT:    [[DST:%.*]] = getelementptr inbounds nuw i8, ptr [[A]], i64 [[INDVARS_IV]]
 ; CHECK-NEXT:    store i8 [[V1]], ptr [[DST]], align 1
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
-; CHECK-NEXT:    [[TMP2:%.*]] = trunc nuw i64 [[INDVARS_IV]] to i32
-; CHECK-NEXT:    [[DONE:%.*]] = icmp sgt i32 [[TMP2]], 9998
+; CHECK-NEXT:    [[LFTR_WIDEIV:%.*]] = trunc i64 [[INDVARS_IV_NEXT]] to i32
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xortator wrote:

Should actually be provable because `add` has `nuw nsw`.

https://github.com/llvm/llvm-project/pull/231697