[TEST][LICM] Add test cases on widenable condition hoisting opportunity

[skatkov]

llvm/test/Transforms/LICM/explicit_guards.ll

132

I would add a description of opportunity.
If we hoist WC we could hoist and as well otherwise it prevents us from doing that.

[skatkov]

And actually instead of NFC tag you can just say [TEST]

[mkazantsev]

llvm/test/Transforms/LICM/explicit_guards.ll

156

Please add a test where wc goes before the icmp7 (see my comment to D149374).

[aleksandr.popov]

llvm/test/Transforms/LICM/explicit_guards.ll

132

I would add a description of opportunity.

Thanks, added

156

Done

llvm/test/Transforms/LICM/explicit_guards.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -S -aa-pipeline=basic-aa -passes='require<opt-remark-emit>,make-guards-explicit,loop-mssa(licm)' < %s | FileCheck %s
 
 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
 ; hoisting them is not profitable because it can prevent guard widening
 ; in loop.
 ; If we want to widen guards in branch form, we need to generate them
 ; at the point of widenable_condition call
 ; (see https://github.com/llvm/llvm-project/issues/60234). Because of
loop:
   call void(i1, ...) @llvm.experimental.guard(i1 %guard_cond) [ "deopt"() ]
   %loop_cond = icmp slt i32 %iv, %M
   %iv.next = add i32 %iv, 1
   br i1 %loop_cond, label %loop, label %exit
 
 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
+}