From d5f1adcf6651a1c10400ad7b1517272ea8e81c53 Mon Sep 17 00:00:00 2001
From: Max Kazantsev <mkazantsev@azul.com>
Date: Fri, 28 Apr 2023 17:52:54 +0700
Subject: [PATCH] [TEST][LICM] Add test cases on widenable condition hoisting
 opportunity

Patch by Aleksandr Popov!

Differential Revision: https://reviews.llvm.org/D149373
---
 llvm/test/Transforms/LICM/explicit_guards.ll | 108 +++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)

diff --git a/llvm/test/Transforms/LICM/explicit_guards.ll b/llvm/test/Transforms/LICM/explicit_guards.ll
index 469acf1..84e5517 100644
--- a/llvm/test/Transforms/LICM/explicit_guards.ll
+++ b/llvm/test/Transforms/LICM/explicit_guards.ll
@@ -3,6 +3,8 @@
 
 declare void @llvm.experimental.guard(i1,...)
 declare void @maythrow()
+declare void @llvm.experimental.deoptimize.isVoid(...)
+declare i1 @llvm.experimental.widenable.condition()
 
 ; Make sure that we do not hoist widenable_cond out of loop.
 ; Widenable conditions don't actually alias anything or throw, however
@@ -125,3 +127,109 @@ loop:
 exit:
   ret void
 }
+
+; TODO: Hoist widenable condition out of loop since it's the only
+; non-invariant operand of its user. If we hoist wc here, we can hoist
+; `and` as well, otherwise it prevents us from doing that.
+define void @hoist_widenable_cond_1(ptr %p, i32 %x) {
+; CHECK-LABEL: @hoist_widenable_cond_1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LOAD:%.*]] = load atomic i32, ptr [[P:%.*]] unordered, align 8
+; CHECK-NEXT:    [[ICMP7:%.*]] = icmp ult i32 0, [[LOAD]]
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[ICMP:%.*]] = icmp ult i32 [[IV]], [[X:%.*]]
+; CHECK-NEXT:    br i1 [[ICMP]], label [[LOOP_BODY:%.*]], label [[EXIT:%.*]]
+; CHECK:       loop.body:
+; CHECK-NEXT:    [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
+; CHECK-NEXT:    [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[ICMP7]], [[WIDENABLE_COND]]
+; CHECK-NEXT:    br i1 [[EXIPLICIT_GUARD_COND]], label [[GUARDED]], label [[DEOPT:%.*]]
+; CHECK:       deopt:
+; CHECK-NEXT:    call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) [ "deopt"() ]
+; CHECK-NEXT:    ret void
+; CHECK:       guarded:
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i32 [[IV]], 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %load = load atomic i32, ptr %p unordered, align 8
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ %iv.next, %guarded ], [ 0, %entry ]
+  %icmp = icmp ult i32 %iv, %x
+  br i1 %icmp, label %loop.body, label %exit
+
+loop.body:
+  %icmp7 = icmp ult i32 0, %load
+  %widenable_cond = call i1 @llvm.experimental.widenable.condition()
+  %exiplicit_guard_cond = and i1 %icmp7, %widenable_cond
+  br i1 %exiplicit_guard_cond, label %guarded, label %deopt
+
+deopt:
+  call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) [ "deopt"() ]
+  ret void
+
+guarded:
+  %iv.next = add nuw nsw i32 %iv, 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+; Same as hoist_widenable_cond_1 test, but widenable condition goes before
+; icmp - the second operand of wc's user.
+; TODO: Hoist widenable condition out of loop.
+define void @hoist_widenable_cond_2(ptr %p, i32 %x) {
+; CHECK-LABEL: @hoist_widenable_cond_2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LOAD:%.*]] = load atomic i32, ptr [[P:%.*]] unordered, align 8
+; CHECK-NEXT:    [[ICMP7:%.*]] = icmp ult i32 0, [[LOAD]]
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[ICMP:%.*]] = icmp ult i32 [[IV]], [[X:%.*]]
+; CHECK-NEXT:    br i1 [[ICMP]], label [[LOOP_BODY:%.*]], label [[EXIT:%.*]]
+; CHECK:       loop.body:
+; CHECK-NEXT:    [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
+; CHECK-NEXT:    [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[ICMP7]], [[WIDENABLE_COND]]
+; CHECK-NEXT:    br i1 [[EXIPLICIT_GUARD_COND]], label [[GUARDED]], label [[DEOPT:%.*]]
+; CHECK:       deopt:
+; CHECK-NEXT:    call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) [ "deopt"() ]
+; CHECK-NEXT:    ret void
+; CHECK:       guarded:
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i32 [[IV]], 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %load = load atomic i32, ptr %p unordered, align 8
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ %iv.next, %guarded ], [ 0, %entry ]
+  %icmp = icmp ult i32 %iv, %x
+  br i1 %icmp, label %loop.body, label %exit
+
+loop.body:
+  %widenable_cond = call i1 @llvm.experimental.widenable.condition()
+  %icmp7 = icmp ult i32 0, %load
+  %exiplicit_guard_cond = and i1 %icmp7, %widenable_cond
+  br i1 %exiplicit_guard_cond, label %guarded, label %deopt
+
+deopt:
+  call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) [ "deopt"() ]
+  ret void
+
+guarded:
+  %iv.next = add nuw nsw i32 %iv, 1
+  br label %loop.header
+
+exit:
+  ret void
+}
-- 
2.7.4