1 files changed, 185 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LICM/sink-from-preheader.ll b/llvm/test/Transforms/LICM/sink-from-preheader.ll
new file mode 100644
index 0000000..bbe3d3b
--- /dev/null
+++ b/llvm/test/Transforms/LICM/sink-from-preheader.ll
@@ -0,0 +1,185 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=licm -verify-memoryssa -S | FileCheck %s
+
+; We perform sinking here, Changed flag should be set properly.
+define i32 @test(i32 %a, i32 %b, i32 %N) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[IV_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+entry:
+  %add = add i32 %a, %b
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i32 %iv, 1
+  %cmp = icmp slt i32 %iv.next, %N
+  br i1 %cmp, label %loop, label %exit
+
+exit:
+  ret i32 %add
+}
+
+define i32 @test_with_unused_load(i32 %a, ptr %b, i32 %N) {
+; CHECK-LABEL: @test_with_unused_load(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[IV_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[LOAD:%.*]] = load i32, ptr [[B:%.*]], align 4
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A:%.*]], [[LOAD]]
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+entry:
+  %load = load i32, ptr %b
+  %add = add i32 %a, %load
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i32 %iv, 1
+  %cmp = icmp slt i32 %iv.next, %N
+  br i1 %cmp, label %loop, label %exit
+
+exit:
+  ret i32 %add
+}
+
+define i32 @test_with_unused_load_modified_store(i32 %a, ptr %b, i32 %N) {
+; CHECK-LABEL: @test_with_unused_load_modified_store(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LOAD:%.*]] = load i32, ptr [[B:%.*]], align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], [[A:%.*]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[IV_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[SMAX:%.*]] = phi i32 [ [[IV_NEXT]], [[LOOP]] ]
+; CHECK-NEXT:    store i32 [[SMAX]], ptr [[B]], align 4
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A]], [[LOAD]]
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+entry:
+  %load = load i32, ptr %b
+  %add = add i32 %a, %load
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i32 %iv, %a
+  store i32 %iv.next, ptr %b
+  %cmp = icmp slt i32 %iv.next, %N
+  br i1 %cmp, label %loop, label %exit
+
+exit:
+  ret i32 %add
+}
+
+; Volatile loads must not be sunk.
+define i32 @test_with_volatile_load_no_sink(i32 %a, ptr %b, i32 %N) {
+; CHECK-LABEL: @test_with_volatile_load_no_sink(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LD:%.*]] = load volatile i32, ptr [[B:%.*]], align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[IV_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A:%.*]], [[LD]]
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+entry:
+  %ld = load volatile i32, ptr %b, align 4
+  %add = add i32 %a, %ld
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i32 %iv, 1
+  %cmp = icmp slt i32 %iv.next, %N
+  br i1 %cmp, label %loop, label %exit
+
+exit:
+  ret i32 %add
+}
+
+; Ordered/atomic loads must not be sunk.
+define i32 @test_with_atomic_load_no_sink(i32 %a, ptr %b, i32 %N) {
+; CHECK-LABEL: @test_with_atomic_load_no_sink(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LD:%.*]] = load atomic i32, ptr [[B:%.*]] acquire, align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[IV_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A:%.*]], [[LD]]
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+entry:
+  %ld = load atomic i32, ptr %b acquire, align 4
+  %add = add i32 %a, %ld
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i32 %iv, 1
+  %cmp = icmp slt i32 %iv.next, %N
+  br i1 %cmp, label %loop, label %exit
+
+exit:
+  ret i32 %add
+}
+
+declare void @clobber(ptr)
+
+; Calls that may write memory in the loop should prevent sinking the load.
+define i32 @test_with_unused_load_clobbered_by_call(i32 %a, ptr %b, i32 %N) {
+; CHECK-LABEL: @test_with_unused_load_clobbered_by_call(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LD:%.*]] = load i32, ptr [[B:%.*]], align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    call void @clobber(ptr [[B]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[IV_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A:%.*]], [[LD]]
+; CHECK-NEXT:    ret i32 [[ADD]]
+;
+entry:
+  %ld = load i32, ptr %b, align 4
+  %add = add i32 %a, %ld
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i32 %iv, 1
+  call void @clobber(ptr %b)
+  %cmp = icmp slt i32 %iv.next, %N
+  br i1 %cmp, label %loop, label %exit
+
+exit:
+  ret i32 %add
+}