[SCEV] Add test for pushing constant add into zext.

Adds a SCEV-only tests for
#151227.

Author: fhahn

llvm/test/Analysis/ScalarEvolution/zext-add.ll

@@ -0,0 +1,52 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes='print<scalar-evolution>' -disable-output %s 2>&1 | FileCheck %s
+
+declare i1 @cond()
+
+define void @test_push_constant_into_zext(ptr %dst, ptr %src, i32 %n, i64 %offset) {
+; CHECK-LABEL: 'test_push_constant_into_zext'
+; CHECK-NEXT:  Classifying expressions for: @test_push_constant_into_zext
+; CHECK-NEXT:    %outer.ptr = phi ptr [ %src, %entry ], [ %ptr.iv.next, %inner.loop ]
+; CHECK-NEXT:    --> %outer.ptr U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %outer.loop: Variant, %inner.loop: Invariant }
+; CHECK-NEXT:    %c = call i1 @cond()
+; CHECK-NEXT:    --> %c U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %outer.loop: Variant, %inner.loop: Invariant }
+; CHECK-NEXT:    %iv = phi i32 [ 0, %outer.loop ], [ %iv.next, %inner.loop ]
+; CHECK-NEXT:    --> {0,+,1}<nuw><nsw><%inner.loop> U: [0,2147483647) S: [0,2147483647) Exits: (-1 + (1 smax %n))<nsw> LoopDispositions: { %inner.loop: Computable, %outer.loop: Variant }
+; CHECK-NEXT:    %ptr.iv = phi ptr [ %src, %outer.loop ], [ %ptr.iv.next, %inner.loop ]
+; CHECK-NEXT:    --> {%src,+,%offset}<%inner.loop> U: full-set S: full-set Exits: (((zext i32 (-1 + (1 smax %n))<nsw> to i64) * %offset) + %src) LoopDispositions: { %inner.loop: Computable, %outer.loop: Variant }
+; CHECK-NEXT:    %l = load i8, ptr %outer.ptr, align 1
+; CHECK-NEXT:    --> %l U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %inner.loop: Variant, %outer.loop: Variant }
+; CHECK-NEXT:    %ptr.iv.next = getelementptr i8, ptr %ptr.iv, i64 %offset
+; CHECK-NEXT:    --> {(%offset + %src),+,%offset}<%inner.loop> U: full-set S: full-set Exits: (((1 + (zext i32 (-1 + (1 smax %n))<nsw> to i64))<nuw><nsw> * %offset) + %src) LoopDispositions: { %inner.loop: Computable, %outer.loop: Variant }
+; CHECK-NEXT:    %iv.next = add i32 %iv, 1
+; CHECK-NEXT:    --> {1,+,1}<nuw><nsw><%inner.loop> U: [1,-2147483648) S: [1,-2147483648) Exits: (1 smax %n) LoopDispositions: { %inner.loop: Computable, %outer.loop: Variant }
+; CHECK-NEXT:  Determining loop execution counts for: @test_push_constant_into_zext
+; CHECK-NEXT:  Loop %inner.loop: backedge-taken count is (-1 + (1 smax %n))<nsw>
+; CHECK-NEXT:  Loop %inner.loop: constant max backedge-taken count is i32 2147483646
+; CHECK-NEXT:  Loop %inner.loop: symbolic max backedge-taken count is (-1 + (1 smax %n))<nsw>
+; CHECK-NEXT:  Loop %inner.loop: Trip multiple is 1
+; CHECK-NEXT:  Loop %outer.loop: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %outer.loop: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %outer.loop: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  br label %outer.loop
+
+outer.loop:
+  %outer.ptr = phi ptr [ %src, %entry ], [ %ptr.iv.next, %inner.loop ]
+  %c = call i1 @cond()
+  br i1 %c, label %inner.loop, label %exit
+
+inner.loop:
+  %iv = phi i32 [ 0, %outer.loop ], [ %iv.next, %inner.loop ]
+  %ptr.iv = phi ptr [ %src, %outer.loop ], [ %ptr.iv.next, %inner.loop ]
+  %l = load i8, ptr %outer.ptr, align 1
+  %ptr.iv.next = getelementptr i8, ptr %ptr.iv, i64 %offset
+  store i8 %l, ptr %dst, align 2
+  %iv.next = add i32 %iv, 1
+  %ec = icmp slt i32 %iv.next, %n
+  br i1 %ec, label %inner.loop, label %outer.loop
+
+exit:
+  ret void
+}