From 1665cb0630773091bc282f669e38ae93a1110c75 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Thu, 15 Jun 2023 10:15:12 +0100
Subject: [PATCH] [LSR] Add test cases showing bad handling of extends of
 post-inc uses.

Tests from #38847, #62852.
---
 .../LoopStrengthReduce/postinc-iv-used-by-urem.ll  | 88 ++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 llvm/test/Transforms/LoopStrengthReduce/postinc-iv-used-by-urem.ll

diff --git a/llvm/test/Transforms/LoopStrengthReduce/postinc-iv-used-by-urem.ll b/llvm/test/Transforms/LoopStrengthReduce/postinc-iv-used-by-urem.ll
new file mode 100644
index 0000000..9df60e0
--- /dev/null
+++ b/llvm/test/Transforms/LoopStrengthReduce/postinc-iv-used-by-urem.ll
@@ -0,0 +1,88 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt -loop-reduce -S %s | FileCheck %s
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+declare void @use(i64)
+
+define i32 @test_pr38847() {
+; CHECK-LABEL: define i32 @test_pr38847() {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[LSR_IV:%.*]] = phi i64 [ [[LSR_IV_NEXT:%.*]], [[LOOP]] ], [ 1, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    call void @use(i64 [[LSR_IV]])
+; CHECK-NEXT:    [[LSR_IV_NEXT]] = add nsw i64 [[LSR_IV]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[LSR_IV_NEXT]] to i8
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i8 [[TMP1]], -1
+; CHECK-NEXT:    br i1 [[CMP2]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[TMP0:%.*]] = udiv i64 [[LSR_IV_NEXT]], 9
+; CHECK-NEXT:    [[TMP1:%.*]] = mul i64 [[TMP0]], 4294967287
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[TMP1]], [[LSR_IV_NEXT]]
+; CHECK-NEXT:    [[TMP:%.*]] = trunc i64 [[TMP2]] to i32
+; CHECK-NEXT:    ret i32 [[TMP]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i8 [ 1, %entry ], [ %iv.next, %loop ]
+  %iv.next = add nsw i8 %iv, -1
+  %ext = zext i8 %iv to i64
+  call void @use(i64 %ext)
+  %cmp2 = icmp sgt i8 %iv.next, -1
+  br i1 %cmp2, label %loop, label %exit
+
+exit:
+  %sext = sext i8 %iv.next to i32
+  %rem = urem i32 %sext, 9
+  ret i32 %rem
+}
+
+define i32 @test_pr62852() {
+; CHECK-LABEL: define i32 @test_pr62852() {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[LSR_IV4:%.*]] = phi i64 [ [[LSR_IV_NEXT5:%.*]], [[LOOP]] ], [ -1, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[LSR_IV1:%.*]] = phi i64 [ [[LSR_IV_NEXT2:%.*]], [[LOOP]] ], [ 1, [[ENTRY]] ]
+; CHECK-NEXT:    [[LSR_IV:%.*]] = phi i64 [ [[LSR_IV_NEXT:%.*]], [[LOOP]] ], [ 2, [[ENTRY]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[LSR_IV4]], 1
+; CHECK-NEXT:    call void @use(i64 [[TMP0]])
+; CHECK-NEXT:    [[LSR_IV_NEXT]] = add nsw i64 [[LSR_IV]], -1
+; CHECK-NEXT:    [[TMP:%.*]] = trunc i64 [[LSR_IV_NEXT]] to i32
+; CHECK-NEXT:    [[LSR_IV_NEXT2]] = add nsw i64 [[LSR_IV1]], -1
+; CHECK-NEXT:    [[LSR_IV_NEXT5]] = add nsw i64 [[LSR_IV4]], 1
+; CHECK-NEXT:    [[CMP6_1:%.*]] = icmp sgt i32 [[TMP]], 0
+; CHECK-NEXT:    br i1 [[CMP6_1]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    call void @use(i64 [[LSR_IV_NEXT]])
+; CHECK-NEXT:    call void @use(i64 [[LSR_IV_NEXT5]])
+; CHECK-NEXT:    [[TMP1:%.*]] = udiv i64 [[LSR_IV_NEXT2]], 53
+; CHECK-NEXT:    [[TMP2:%.*]] = mul i64 [[TMP1]], 4294967243
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[TMP2]], [[LSR_IV_NEXT]]
+; CHECK-NEXT:    [[TMP4:%.*]] = add i64 [[TMP3]], -1
+; CHECK-NEXT:    [[TMP3:%.*]] = trunc i64 [[TMP4]] to i32
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv.1 = phi i32 [ 1, %entry ], [ %dec.1, %loop ]
+  %iv.2 = phi i64 [ 0, %entry ], [ %inc.1, %loop ]
+  %inc.1 = add nsw i64 %iv.2, 1
+  %dec.1 = add nsw i32 %iv.1, -1
+  call void @use(i64 %iv.2)
+  %cmp6.1 = icmp sgt i32 %iv.1, 0
+  br i1 %cmp6.1, label %loop, label %exit
+
+exit:
+  %iv.1.ext = zext i32 %iv.1 to i64
+  call void @use(i64 %iv.1.ext)
+  call void @use(i64 %iv.2)
+  %rem = urem i32 %dec.1, 53
+  ret i32 %rem
+}
-- 
2.7.4