From 37bf0a10fb4cee10f4acbb7da453e7c19c8ee599 Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov@redhat.com>
Date: Fri, 24 Jan 2025 17:10:10 +0100
Subject: [PATCH] [SCEV] Add test for #123550 (NFC)

---
 .../test/Analysis/ScalarEvolution/pr123550.ll | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 llvm/test/Analysis/ScalarEvolution/pr123550.ll

diff --git a/llvm/test/Analysis/ScalarEvolution/pr123550.ll b/llvm/test/Analysis/ScalarEvolution/pr123550.ll
new file mode 100644
index 000000000000..c1f2051248a1
--- /dev/null
+++ b/llvm/test/Analysis/ScalarEvolution/pr123550.ll
@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -disable-output -passes='print<scalar-evolution>' < %s 2>&1 | FileCheck %s
+
+; FIXME: This is a miscompile.
+define i32 @test() {
+; CHECK-LABEL: 'test'
+; CHECK-NEXT:  Classifying expressions for: @test
+; CHECK-NEXT:    %phi = phi i32 [ -173, %bb ], [ %sub, %loop ]
+; CHECK-NEXT:    --> (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw> U: empty-set S: empty-set Exits: -173 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %iv2 = phi i32 [ 1, %bb ], [ %iv2.inc, %loop ]
+; CHECK-NEXT:    --> {1,+,1}<nuw><nsw><%loop> U: [1,2) S: [1,2) Exits: 1 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %srem = srem i32 729259140, %phi
+; CHECK-NEXT:    --> (729259140 + (-1 * (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw> * (729259140 /u (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw>)))<nuw><nsw> U: empty-set S: empty-set Exits: 729259140 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %trunc = trunc i32 %iv2 to i8
+; CHECK-NEXT:    --> {1,+,1}<%loop> U: [1,2) S: [1,2) Exits: 1 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %urem = urem i8 -83, %trunc
+; CHECK-NEXT:    --> (-83 + ((-83 /u {1,+,1}<%loop>) * {-1,+,-1}<%loop>)) U: [0,1) S: [0,1) Exits: 0 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %zext = zext i8 %urem to i32
+; CHECK-NEXT:    --> (zext i8 (-83 + ((-83 /u {1,+,1}<%loop>) * {-1,+,-1}<%loop>)) to i32) U: [0,1) S: [0,1) Exits: 0 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %sub = sub i32 0, %zext
+; CHECK-NEXT:    --> (-1 * (zext i8 (-83 + ((-83 /u {1,+,1}<%loop>) * {-1,+,-1}<%loop>)) to i32))<nuw><nsw> U: [0,1) S: [0,1) Exits: 0 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %iv2.inc = add i32 %iv2, 1
+; CHECK-NEXT:    --> {2,+,1}<nuw><nsw><%loop> U: [2,3) S: [2,3) Exits: 2 LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %srem.lcssa = phi i32 [ %srem, %loop ]
+; CHECK-NEXT:    --> (729259140 + (-1 * (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw> * (729259140 /u (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw>)))<nuw><nsw> U: empty-set S: empty-set --> 729259140 U: [729259140,729259141) S: [729259140,729259141)
+; CHECK-NEXT:  Determining loop execution counts for: @test
+; CHECK-NEXT:  Loop %loop: backedge-taken count is i32 0
+; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is i32 0
+; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is i32 0
+; CHECK-NEXT:  Loop %loop: Trip multiple is 1
+;
+bb:
+  br label %loop
+
+loop:
+  %phi = phi i32 [ -173, %bb ], [ %sub, %loop ]
+  %iv2 = phi i32 [ 1, %bb ], [ %iv2.inc, %loop ]
+  %srem = srem i32 729259140, %phi
+  %trunc = trunc i32 %iv2 to i8
+  %urem = urem i8 -83, %trunc
+  %zext = zext i8 %urem to i32
+  %sub = sub i32 0, %zext
+  %iv2.inc = add i32 %iv2, 1
+  %icmp = icmp eq i32 %zext, 0
+  br i1 %icmp, label %exit, label %loop
+
+exit:
+  %srem.lcssa = phi i32 [ %srem, %loop ]
+  ret i32 %srem.lcssa
+}