[DSE] Precommit test case with loop carried dependence.

llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-loop-carried-dependence.ll

@@ -0,0 +1,140 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+
+; RUN: opt -dse -S %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-n32:64-v256:256:256-v512:512:512"
+
+declare void @use(i32)
+
+; Test cases with a loop carried dependence in %loop.2, where %l.2 reads the
+; value stored by the previous iteration. Hence, the store in %loop.2 is not
+; dead at the end of the function or after the call to lifetime.end().
+
+define void @test.1() {
+; CHECK-LABEL: @test.1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca [100 x i32], align 4
+; CHECK-NEXT:    br label [[LOOP_1:%.*]]
+; CHECK:       loop.1:
+; CHECK-NEXT:    [[IV_1:%.*]] = phi i64 [ 1, [[ENTRY:%.*]] ], [ [[IV_1_NEXT:%.*]], [[LOOP_1]] ]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds [100 x i32], [100 x i32]* [[A]], i64 0, i64 [[IV_1]]
+; CHECK-NEXT:    store i32 0, i32* [[ARRAYIDX1]], align 4
+; CHECK-NEXT:    [[IV_1_NEXT]] = add nsw i64 [[IV_1]], 1
+; CHECK-NEXT:    [[C_1:%.*]] = icmp slt i64 [[IV_1_NEXT]], 100
+; CHECK-NEXT:    br i1 [[C_1]], label [[LOOP_1]], label [[LOOP_2_PH:%.*]]
+; CHECK:       loop.2.ph:
+; CHECK-NEXT:    br label [[LOOP_2:%.*]]
+; CHECK:       loop.2:
+; CHECK-NEXT:    [[IV_2:%.*]] = phi i64 [ [[IV_2_NEXT:%.*]], [[LOOP_2]] ], [ 0, [[LOOP_2_PH]] ]
+; CHECK-NEXT:    [[PTR_IV_2:%.*]] = getelementptr inbounds [100 x i32], [100 x i32]* [[A]], i64 0, i64 [[IV_2]]
+; CHECK-NEXT:    [[L_0:%.*]] = load i32, i32* [[PTR_IV_2]], align 4
+; CHECK-NEXT:    call void @use(i32 [[L_0]])
+; CHECK-NEXT:    [[L_1:%.*]] = load i32, i32* [[PTR_IV_2]], align 4
+; CHECK-NEXT:    call void @use(i32 [[L_1]])
+; CHECK-NEXT:    [[IV_2_NEXT]] = add nsw i64 [[IV_2]], 1
+; CHECK-NEXT:    [[C_2:%.*]] = icmp slt i64 [[IV_2_NEXT]], 100
+; CHECK-NEXT:    br i1 [[C_2]], label [[LOOP_2]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %A = alloca [100 x i32], align 4
+  br label %loop.1
+
+loop.1:
+  %iv.1 = phi i64 [ 1, %entry ], [ %iv.1.next, %loop.1 ]
+  %arrayidx1 = getelementptr inbounds [100 x i32], [100 x i32]* %A, i64 0, i64 %iv.1
+  store i32 0, i32* %arrayidx1, align 4
+  %iv.1.next = add nsw i64 %iv.1, 1
+  %c.1 = icmp slt i64 %iv.1.next, 100
+  br i1 %c.1, label %loop.1, label %loop.2.ph
+
+loop.2.ph:
+  br label %loop.2
+
+loop.2:
+  %iv.2 = phi i64 [ %iv.2.next, %loop.2 ], [ 0, %loop.2.ph ]
+  %ptr.iv.2 = getelementptr inbounds [100 x i32], [100 x i32]* %A, i64 0, i64 %iv.2
+  %l.0 = load i32, i32* %ptr.iv.2, align 4
+  call void @use(i32 %l.0)
+  %add = add nsw i64 %iv.2, 1
+  %ptr.iv.2.add.1 = getelementptr inbounds [100 x i32], [100 x i32]* %A, i64 0, i64 %add
+  store i32 10, i32* %ptr.iv.2.add.1, align 4
+  %l.1 = load i32, i32* %ptr.iv.2, align 4
+  call void @use(i32 %l.1)
+  %iv.2.next = add nsw i64 %iv.2, 1
+  %c.2 = icmp slt i64 %iv.2.next, 100
+  br i1 %c.2, label %loop.2, label %exit
+
+exit:
+  ret void
+}
+
+define void @test.2() {
+; CHECK-LABEL: @test.2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca [100 x i32], align 4
+; CHECK-NEXT:    [[A_CAST:%.*]] = bitcast [100 x i32]* [[A]] to i8*
+; CHECK-NEXT:    br label [[LOOP_1:%.*]]
+; CHECK:       loop.1:
+; CHECK-NEXT:    [[IV_1:%.*]] = phi i64 [ 1, [[ENTRY:%.*]] ], [ [[IV_1_NEXT:%.*]], [[LOOP_1]] ]
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds [100 x i32], [100 x i32]* [[A]], i64 0, i64 [[IV_1]]
+; CHECK-NEXT:    store i32 0, i32* [[ARRAYIDX1]], align 4
+; CHECK-NEXT:    [[IV_1_NEXT]] = add nsw i64 [[IV_1]], 1
+; CHECK-NEXT:    [[C_1:%.*]] = icmp slt i64 [[IV_1_NEXT]], 100
+; CHECK-NEXT:    br i1 [[C_1]], label [[LOOP_1]], label [[LOOP_2_PH:%.*]]
+; CHECK:       loop.2.ph:
+; CHECK-NEXT:    br label [[LOOP_2:%.*]]
+; CHECK:       loop.2:
+; CHECK-NEXT:    [[IV_2:%.*]] = phi i64 [ [[IV_2_NEXT:%.*]], [[LOOP_2]] ], [ 0, [[LOOP_2_PH]] ]
+; CHECK-NEXT:    [[PTR_IV_2:%.*]] = getelementptr inbounds [100 x i32], [100 x i32]* [[A]], i64 0, i64 [[IV_2]]
+; CHECK-NEXT:    [[L_0:%.*]] = load i32, i32* [[PTR_IV_2]], align 4
+; CHECK-NEXT:    call void @use(i32 [[L_0]])
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i64 [[IV_2]], 1
+; CHECK-NEXT:    [[PTR_IV_2_ADD_1:%.*]] = getelementptr inbounds [100 x i32], [100 x i32]* [[A]], i64 0, i64 [[ADD]]
+; CHECK-NEXT:    store i32 10, i32* [[PTR_IV_2_ADD_1]], align 4
+; CHECK-NEXT:    [[L_1:%.*]] = load i32, i32* [[PTR_IV_2]], align 4
+; CHECK-NEXT:    call void @use(i32 [[L_1]])
+; CHECK-NEXT:    [[IV_2_NEXT]] = add nsw i64 [[IV_2]], 1
+; CHECK-NEXT:    [[C_2:%.*]] = icmp slt i64 [[IV_2_NEXT]], 100
+; CHECK-NEXT:    br i1 [[C_2]], label [[LOOP_2]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0i8(i64 400, i8* nonnull [[A_CAST]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %A = alloca [100 x i32], align 4
+  %A.cast = bitcast [100 x i32]* %A to i8*
+  br label %loop.1
+
+loop.1:
+  %iv.1 = phi i64 [ 1, %entry ], [ %iv.1.next, %loop.1 ]
+  %arrayidx1 = getelementptr inbounds [100 x i32], [100 x i32]* %A, i64 0, i64 %iv.1
+  store i32 0, i32* %arrayidx1, align 4
+  %iv.1.next = add nsw i64 %iv.1, 1
+  %c.1 = icmp slt i64 %iv.1.next, 100
+  br i1 %c.1, label %loop.1, label %loop.2.ph
+
+loop.2.ph:
+  br label %loop.2
+
+loop.2:
+  %iv.2 = phi i64 [ %iv.2.next, %loop.2 ], [ 0, %loop.2.ph ]
+  %ptr.iv.2 = getelementptr inbounds [100 x i32], [100 x i32]* %A, i64 0, i64 %iv.2
+  %l.0 = load i32, i32* %ptr.iv.2, align 4
+  call void @use(i32 %l.0)
+  %add = add nsw i64 %iv.2, 1
+  %ptr.iv.2.add.1 = getelementptr inbounds [100 x i32], [100 x i32]* %A, i64 0, i64 %add
+  store i32 10, i32* %ptr.iv.2.add.1, align 4
+  %l.1 = load i32, i32* %ptr.iv.2, align 4
+  call void @use(i32 %l.1)
+  %iv.2.next = add nsw i64 %iv.2, 1
+  %c.2 = icmp slt i64 %iv.2.next, 100
+  br i1 %c.2, label %loop.2, label %exit
+
+exit:
+  call void @llvm.lifetime.end.p0i8(i64 400, i8* nonnull %A.cast) #5
+  ret void
+}
+
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)