Index: tests_lit/llvm2ice_tests/nacl-atomic-cmpxchg-optimization.ll |
diff --git a/tests_lit/llvm2ice_tests/nacl-atomic-cmpxchg-optimization.ll b/tests_lit/llvm2ice_tests/nacl-atomic-cmpxchg-optimization.ll |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5972df9245152a583fefd5c585ef82a40ccadc1d |
--- /dev/null |
+++ b/tests_lit/llvm2ice_tests/nacl-atomic-cmpxchg-optimization.ll |
@@ -0,0 +1,150 @@ |
+; This tests the optimization of atomic cmpxchg w/ following cmp + branches. |
+ |
+; RUN: %llvm2ice -O2 --verbose none %s | FileCheck %s --check-prefix=O2 |
+; RUN: %llvm2ice -Om1 --verbose none %s | FileCheck %s --check-prefix=OM1 |
+; RUN: %llvm2ice -O2 --verbose none %s \ |
+; RUN: | llvm-mc -arch=x86 -x86-asm-syntax=intel -filetype=obj |
+; RUN: %llvm2ice -Om1 --verbose none %s \ |
+; RUN: | llvm-mc -arch=x86 -x86-asm-syntax=intel -filetype=obj |
+; RUN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s |
+; RUN: %llvm2iceinsts %s | %szdiff %s | FileCheck --check-prefix=DUMP %s |
+; RUN: %llvm2iceinsts --pnacl %s | %szdiff %s \ |
+; RUN: | FileCheck --check-prefix=DUMP %s |
+ |
+declare i32 @llvm.nacl.atomic.cmpxchg.i32(i32*, i32, i32, i32, i32) |
+ |
+ |
+; Test that a cmpxchg followed by icmp eq and branch can be optimized to |
+; reuse the flags set by the cmpxchg instruction itself. |
+; This is only expected to work w/ O2, based on lightweight liveness. |
+; (Or if we had other means to detect the only use). |
+declare void @use_value(i32); |
+ |
+define i32 @test_atomic_cmpxchg_loop(i32 %iptr, i32 %expected, i32 %desired) { |
+entry: |
+ br label %loop |
+ |
+loop: |
+ %expected_loop = phi i32 [ %expected, %entry ], [ %old, %loop ] |
+ %succeeded_first_try = phi i32 [ 1, %entry ], [ 2, %loop ] |
+ %ptr = inttoptr i32 %iptr to i32* |
+ %old = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 %expected_loop, |
+ i32 %desired, i32 6, i32 6) |
+ %success = icmp eq i32 %expected_loop, %old |
+ br i1 %success, label %done, label %loop |
+ |
+done: |
+ call void @use_value(i32 %old) |
+ ret i32 %succeeded_first_try |
+} |
+; O2-LABEL: .Ltest_atomic_cmpxchg_loop{{.*}}loop |
+; O2: lock cmpxchg dword ptr [e{{[^a].}}], e{{[^a]}} |
+; O2-NOT: cmp |
+; Make sure the phi assignment for succeeded_first_try is still there. |
+; O2: mov {{.*}}, 2 |
+; O2-NOT: cmp |
+; O2: je |
+; O2-LABEL: .Ltest_atomic_cmpxchg_loop{{.*}}done |
+; Make sure the call isn't accidentally deleted. |
+; O2: call |
+; |
+; Check that the unopt version does have a cmp |
+; OM1-LABEL: .Ltest_atomic_cmpxchg_loop{{.*}}loop |
+; OM1: lock cmpxchg dword ptr [e{{[^a].}}], e{{[^a]}} |
+; OM1: cmp |
+; OM1: je |
+; OM1-LABEL: .Ltest_atomic_cmpxchg_loop{{.*}}done |
+; OM1: call |
+ |
+; Still works if the compare operands are flipped. |
+define i32 @test_atomic_cmpxchg_loop2(i32 %iptr, i32 %expected, i32 %desired) { |
+entry: |
+ br label %loop |
+ |
+loop: |
+ %expected_loop = phi i32 [ %expected, %entry ], [ %old, %loop ] |
+ %ptr = inttoptr i32 %iptr to i32* |
+ %old = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 %expected_loop, |
+ i32 %desired, i32 6, i32 6) |
+ %success = icmp eq i32 %old, %expected_loop |
+ br i1 %success, label %done, label %loop |
+ |
+done: |
+ ret i32 %old |
+} |
+; O2-LABEL: .Ltest_atomic_cmpxchg_loop2{{.*}}loop |
+; O2: lock cmpxchg dword ptr [e{{[^a].}}], e{{[^a]}} |
+; O2-NOT: cmp |
+; O2: je |
+ |
+ |
+; Still works if the compare operands are constants. |
+define i32 @test_atomic_cmpxchg_loop_const(i32 %iptr, i32 %desired) { |
+entry: |
+ br label %loop |
+ |
+loop: |
+ %succeeded_first_try = phi i32 [ 1, %entry ], [ 0, %loop ] |
+ %ptr = inttoptr i32 %iptr to i32* |
+ %old = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, |
+ i32 %desired, i32 6, i32 6) |
+ %success = icmp eq i32 %old, 0 |
+ br i1 %success, label %done, label %loop |
+ |
+done: |
+ ret i32 %succeeded_first_try |
+} |
+; O2-LABEL: .Ltest_atomic_cmpxchg_loop_const{{.*}}loop |
+; O2: lock cmpxchg dword ptr [e{{[^a].}}], e{{[^a]}} |
+; O2-NOT: cmp |
+; O2: je |
+ |
+; This is a case where the flags cannot be reused (compare is for some |
+; other condition). |
+define i32 @test_atomic_cmpxchg_no_opt(i32 %iptr, i32 %expected, i32 %desired) { |
+entry: |
+ br label %loop |
+ |
+loop: |
+ %expected_loop = phi i32 [ %expected, %entry ], [ %old, %loop ] |
+ %ptr = inttoptr i32 %iptr to i32* |
+ %old = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 %expected_loop, |
+ i32 %desired, i32 6, i32 6) |
+ %success = icmp sgt i32 %old, %expected |
+ br i1 %success, label %done, label %loop |
+ |
+done: |
+ ret i32 %old |
+} |
+; O2-LABEL: .Ltest_atomic_cmpxchg_no_opt{{.*}}loop |
+; O2: lock cmpxchg dword ptr [e{{[^a].}}], e{{[^a]}} |
+; O2: mov {{.*}} |
+; O2: cmp |
+; O2: jg |
+ |
+; Another case where the flags cannot be reused (the comparison result |
+; is used somewhere else). |
+define i32 @test_atomic_cmpxchg_no_opt2(i32 %iptr, i32 %expected, i32 %desired) { |
+entry: |
+ br label %loop |
+ |
+loop: |
+ %expected_loop = phi i32 [ %expected, %entry ], [ %old, %loop ] |
+ %ptr = inttoptr i32 %iptr to i32* |
+ %old = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 %expected_loop, |
+ i32 %desired, i32 6, i32 6) |
+ %success = icmp eq i32 %old, %expected |
+ br i1 %success, label %done, label %loop |
+ |
+done: |
+ %r = zext i1 %success to i32 |
+ ret i32 %r |
+} |
+; O2-LABEL: .Ltest_atomic_cmpxchg_no_opt2{{.*}}loop |
+; O2: lock cmpxchg dword ptr [e{{[^a].}}], e{{[^a]}} |
+; O2: mov {{.*}} |
+; O2: cmp |
+; O2: je |
+ |
+; ERRORS-NOT: ICE translation error |
+; DUMP-NOT: SZ |