[llvm] 85fd97e - [MemCpyOpt] Add tests with incorrect memcpy->byval forwarding.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2022-02-16T11:35:14Z
New Revision: 85fd97e3b9dea439301f545945b516d4c3f4ba58

URL: https://github.com/llvm/llvm-project/commit/85fd97e3b9dea439301f545945b516d4c3f4ba58
DIFF: https://github.com/llvm/llvm-project/commit/85fd97e3b9dea439301f545945b516d4c3f4ba58.diff

LOG: [MemCpyOpt] Add tests with incorrect memcpy->byval forwarding.

Add a few test cases with clobbers (writes and lifetime.end) that should
prevent memcpy->byval forwarding, but those clobbers are missed at the
moment.

Added: 
    llvm/test/Transforms/MemCpyOpt/memcpy-byval-forwarding-clobbers.ll

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/MemCpyOpt/memcpy-byval-forwarding-clobbers.ll b/llvm/test/Transforms/MemCpyOpt/memcpy-byval-forwarding-clobbers.ll
new file mode 100644
index 0000000000000..f2eae367dae4d
--- /dev/null
+++ b/llvm/test/Transforms/MemCpyOpt/memcpy-byval-forwarding-clobbers.ll
@@ -0,0 +1,140 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=memcpyopt -S %s | FileCheck %s
+
+declare void @init(i64* nocapture sret(i64) align 8)
+
+declare i1 @check(i64* readonly byval(i64) align 8) readonly argmemonly
+
+declare void @clobber(i8*) argmemonly
+
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg)
+
+; %a.2's lifetime ends before the call to @check. Cannot replace
+; %a.1 with %a.2 in the call to @check.
+; FIXME: Find lifetime.end, prevent optimization.
+define i1 @alloca_forwarding_lifetime_end_clobber() {
+; CHECK-LABEL: @alloca_forwarding_lifetime_end_clobber(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A_1:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[A_2:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[BC_A_1:%.*]] = bitcast i64* [[A_1]] to i8*
+; CHECK-NEXT:    [[BC_A_2:%.*]] = bitcast i64* [[A_2]] to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0i8(i64 8, i8* [[BC_A_2]])
+; CHECK-NEXT:    call void @init(i64* sret(i64) align 8 [[A_2]])
+; CHECK-NEXT:    store i8 0, i8* [[BC_A_2]], align 1
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[BC_A_1]], i8* [[BC_A_2]], i64 8, i1 false)
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0i8(i64 8, i8* [[BC_A_2]])
+; CHECK-NEXT:    [[CALL:%.*]] = call i1 @check(i64* byval(i64) align 8 [[A_2]])
+; CHECK-NEXT:    ret i1 [[CALL]]
+;
+entry:
+  %a.1 = alloca i64, align 8
+  %a.2 = alloca i64, align 8
+  %bc.a.1 = bitcast i64* %a.1 to i8*
+  %bc.a.2 = bitcast i64* %a.2 to i8*
+  call void @llvm.lifetime.start.p0i8(i64 8, i8* %bc.a.2)
+  call void @init(i64* sret(i64) align 8 %a.2)
+  store i8 0, i8* %bc.a.2
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %bc.a.1, i8* %bc.a.2, i64 8, i1 false)
+  call void @llvm.lifetime.end.p0i8(i64 8, i8* %bc.a.2)
+  ;call void @clobber(i8* %bc.a.2)
+  %call = call i1 @check(i64* byval(i64) align 8 %a.1)
+  ret i1 %call
+}
+
+; There is a call clobbering %a.2 before the call to @check. Cannot replace
+; %a.1 with %a.2 in the call to @check.
+; FIXME: Find clobber, prevent optimization.
+define i1 @alloca_forwarding_call_clobber() {
+; CHECK-LABEL: @alloca_forwarding_call_clobber(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A_1:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[A_2:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[BC_A_1:%.*]] = bitcast i64* [[A_1]] to i8*
+; CHECK-NEXT:    [[BC_A_2:%.*]] = bitcast i64* [[A_2]] to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0i8(i64 8, i8* [[BC_A_2]])
+; CHECK-NEXT:    call void @init(i64* sret(i64) align 8 [[A_2]])
+; CHECK-NEXT:    store i8 0, i8* [[BC_A_2]], align 1
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[BC_A_1]], i8* [[BC_A_2]], i64 8, i1 false)
+; CHECK-NEXT:    call void @clobber(i8* [[BC_A_2]])
+; CHECK-NEXT:    [[CALL:%.*]] = call i1 @check(i64* byval(i64) align 8 [[A_2]])
+; CHECK-NEXT:    ret i1 [[CALL]]
+;
+entry:
+  %a.1 = alloca i64, align 8
+  %a.2 = alloca i64, align 8
+  %bc.a.1 = bitcast i64* %a.1 to i8*
+  %bc.a.2 = bitcast i64* %a.2 to i8*
+  call void @llvm.lifetime.start.p0i8(i64 8, i8* %bc.a.2)
+  call void @init(i64* sret(i64) align 8 %a.2)
+  store i8 0, i8* %bc.a.2
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %bc.a.1, i8* %bc.a.2, i64 8, i1 false)
+  call void @clobber(i8* %bc.a.2)
+  %call = call i1 @check(i64* byval(i64) align 8 %a.1)
+  ret i1 %call
+}
+
+define i1 @alloca_forwarding_call_clobber_after() {
+; CHECK-LABEL: @alloca_forwarding_call_clobber_after(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A_1:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[A_2:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[BC_A_1:%.*]] = bitcast i64* [[A_1]] to i8*
+; CHECK-NEXT:    [[BC_A_2:%.*]] = bitcast i64* [[A_2]] to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0i8(i64 8, i8* [[BC_A_2]])
+; CHECK-NEXT:    call void @init(i64* sret(i64) align 8 [[A_2]])
+; CHECK-NEXT:    store i8 0, i8* [[BC_A_2]], align 1
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[BC_A_1]], i8* [[BC_A_2]], i64 8, i1 false)
+; CHECK-NEXT:    [[CALL:%.*]] = call i1 @check(i64* byval(i64) align 8 [[A_2]])
+; CHECK-NEXT:    call void @clobber(i8* [[BC_A_2]])
+; CHECK-NEXT:    ret i1 [[CALL]]
+;
+entry:
+  %a.1 = alloca i64, align 8
+  %a.2 = alloca i64, align 8
+  %bc.a.1 = bitcast i64* %a.1 to i8*
+  %bc.a.2 = bitcast i64* %a.2 to i8*
+  call void @llvm.lifetime.start.p0i8(i64 8, i8* %bc.a.2)
+  call void @init(i64* sret(i64) align 8 %a.2)
+  store i8 0, i8* %bc.a.2
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %bc.a.1, i8* %bc.a.2, i64 8, i1 false)
+  %call = call i1 @check(i64* byval(i64) align 8 %a.1)
+  call void @clobber(i8* %bc.a.2)
+  ret i1 %call
+}
+
+define i1 @alloca_forwarding_unrelated_call_noclobber() {
+; CHECK-LABEL: @alloca_forwarding_unrelated_call_noclobber(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A_1:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[A_2:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[A_3:%.*]] = alloca i64, align 8
+; CHECK-NEXT:    [[BC_A_1:%.*]] = bitcast i64* [[A_1]] to i8*
+; CHECK-NEXT:    [[BC_A_2:%.*]] = bitcast i64* [[A_2]] to i8*
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0i8(i64 8, i8* [[BC_A_2]])
+; CHECK-NEXT:    call void @init(i64* sret(i64) align 8 [[A_2]])
+; CHECK-NEXT:    store i8 0, i8* [[BC_A_2]], align 1
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[BC_A_1]], i8* [[BC_A_2]], i64 8, i1 false)
+; CHECK-NEXT:    [[BC_A_3:%.*]] = bitcast i64* [[A_3]] to i8*
+; CHECK-NEXT:    call void @clobber(i8* [[BC_A_3]])
+; CHECK-NEXT:    [[CALL:%.*]] = call i1 @check(i64* byval(i64) align 8 [[A_2]])
+; CHECK-NEXT:    ret i1 [[CALL]]
+;
+entry:
+  %a.1 = alloca i64, align 8
+  %a.2 = alloca i64, align 8
+  %a.3 = alloca i64, align 8
+  %bc.a.1 = bitcast i64* %a.1 to i8*
+  %bc.a.2 = bitcast i64* %a.2 to i8*
+  call void @llvm.lifetime.start.p0i8(i64 8, i8* %bc.a.2)
+  call void @init(i64* sret(i64) align 8 %a.2)
+  store i8 0, i8* %bc.a.2
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %bc.a.1, i8* %bc.a.2, i64 8, i1 false)
+  %bc.a.3 = bitcast i64* %a.3 to i8*
+  call void @clobber(i8* %bc.a.3)
+  %call = call i1 @check(i64* byval(i64) align 8 %a.1)
+  ret i1 %call
+}
+