From 824e9bb2e33655734eb3e9169ba5c4964cc1861c Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n@gmail.com>
Date: Thu, 27 Apr 2023 23:21:29 -0500
Subject: [PATCH] [ValueTracking] Add tests for checking whether `div`/`rem` is
 safe to speculate; NFC

Differential Revision: https://reviews.llvm.org/D149422
---
 llvm/test/Transforms/LICM/speculate-div.ll | 135 +++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 llvm/test/Transforms/LICM/speculate-div.ll

diff --git a/llvm/test/Transforms/LICM/speculate-div.ll b/llvm/test/Transforms/LICM/speculate-div.ll
new file mode 100644
index 0000000..50e755e
--- /dev/null
+++ b/llvm/test/Transforms/LICM/speculate-div.ll
@@ -0,0 +1,135 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=licm -S | FileCheck %s
+
+declare void @maythrow()
+declare void @use(i16)
+
+define void @sdiv_not_ok(i16 %n, i16 %xx) {
+; CHECK-LABEL: @sdiv_not_ok(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[X:%.*]] = or i16 [[XX:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @maythrow()
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i16 [[N:%.*]], [[X]]
+; CHECK-NEXT:    call void @use(i16 [[DIV]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  %x = or i16 %xx, 1
+  br label %loop
+loop:
+  call void @maythrow()
+  %div = sdiv i16 %n, %x
+  call void @use(i16 %div)
+  br label %loop
+}
+
+define void @srem_not_ok2(i16 %nn, i16 %x) {
+; CHECK-LABEL: @srem_not_ok2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[N:%.*]] = and i16 [[NN:%.*]], 1323
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @maythrow()
+; CHECK-NEXT:    [[DIV:%.*]] = srem i16 [[N]], [[X:%.*]]
+; CHECK-NEXT:    call void @use(i16 [[DIV]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  %n = and i16 %nn, 1323
+  br label %loop
+loop:
+  call void @maythrow()
+  %div = srem i16 %n, %x
+  call void @use(i16 %div)
+  br label %loop
+}
+
+define void @sdiv_ok(i16 %n, i16 %xx) {
+; CHECK-LABEL: @sdiv_ok(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[XO:%.*]] = or i16 [[XX:%.*]], 1
+; CHECK-NEXT:    [[X:%.*]] = and i16 [[XO]], 123
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @maythrow()
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i16 [[N:%.*]], [[X]]
+; CHECK-NEXT:    call void @use(i16 [[DIV]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  %xo = or i16 %xx, 1
+  %x = and i16 %xo, 123
+  br label %loop
+loop:
+  call void @maythrow()
+  %div = sdiv i16 %n, %x
+  call void @use(i16 %div)
+  br label %loop
+}
+
+define void @srem_ok2(i16 %nn, i16 %xx) {
+; CHECK-LABEL: @srem_ok2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[N:%.*]] = and i16 [[NN:%.*]], 123
+; CHECK-NEXT:    [[X:%.*]] = or i16 [[XX:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @maythrow()
+; CHECK-NEXT:    [[DIV:%.*]] = srem i16 [[N]], [[X]]
+; CHECK-NEXT:    call void @use(i16 [[DIV]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  %n = and i16 %nn, 123
+  %x = or i16 %xx, 1
+  br label %loop
+loop:
+  call void @maythrow()
+  %div = srem i16 %n, %x
+  call void @use(i16 %div)
+  br label %loop
+}
+
+define void @udiv_not_ok(i16 %n, i16 %xx) {
+; CHECK-LABEL: @udiv_not_ok(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[X:%.*]] = xor i16 [[XX:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @maythrow()
+; CHECK-NEXT:    [[DIV:%.*]] = udiv i16 [[N:%.*]], [[X]]
+; CHECK-NEXT:    call void @use(i16 [[DIV]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  %x = xor i16 %xx, 1
+  br label %loop
+loop:
+  call void @maythrow()
+  %div = udiv i16 %n, %x
+  call void @use(i16 %div)
+  br label %loop
+}
+
+define void @udiv_ok(i16 %n, i16 %xx) {
+; CHECK-LABEL: @udiv_ok(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[X:%.*]] = or i16 [[XX:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @maythrow()
+; CHECK-NEXT:    [[DIV:%.*]] = udiv i16 [[N:%.*]], [[X]]
+; CHECK-NEXT:    call void @use(i16 [[DIV]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  %x = or i16 %xx, 1
+  br label %loop
+loop:
+  call void @maythrow()
+  %div = udiv i16 %n, %x
+  call void @use(i16 %div)
+  br label %loop
+}
-- 
2.7.4