CodeGen: it turns out that NAND is not the same thing as BIC. At all.

We've been performing the wrong operation on ARM for "atomicrmw nand" for
years, since "a NAND b" is "~(a & b)" rather than ARM's very tempting "a & ~b".
This bled over into the generic expansion pass.

So I assume no-one has ever actually tried to do an atomic nand in the real
world. Oh well.

llvm-svn: 212443

3 files changed, 11 insertions, 7 deletions

diff --git a/llvm/test/CodeGen/AArch64/arm64-atomic-128.ll b/llvm/test/CodeGen/AArch64/arm64-atomic-128.ll
index 0f5b23998ee..3377849f669 100644
--- a/llvm/test/CodeGen/AArch64/arm64-atomic-128.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-atomic-128.ll
@@ -22,8 +22,10 @@ define void @fetch_and_nand(i128* %p, i128 %bits) {
 ; CHECK-LABEL: fetch_and_nand:
 ; CHECK: [[LABEL:.?LBB[0-9]+_[0-9]+]]:
 ; CHECK: ldxp  [[DEST_REGLO:x[0-9]+]], [[DEST_REGHI:x[0-9]+]], [x0]
-; CHECK-DAG: bic    [[SCRATCH_REGLO:x[0-9]+]], [[DEST_REGLO]], x2
-; CHECK-DAG: bic    [[SCRATCH_REGHI:x[0-9]+]], [[DEST_REGHI]], x3
+; CHECK-DAG: and    [[TMP_REGLO:x[0-9]+]], [[DEST_REGLO]], x2
+; CHECK-DAG: and    [[TMP_REGHI:x[0-9]+]], [[DEST_REGHI]], x3
+; CHECK-DAG: mvn    [[SCRATCH_REGLO:x[0-9]+]], [[TMP_REGLO]]
+; CHECK-DAG: mvn    [[SCRATCH_REGHI:x[0-9]+]], [[TMP_REGHI]]
 ; CHECK: stlxp  [[SCRATCH_RES:w[0-9]+]], [[SCRATCH_REGLO]], [[SCRATCH_REGHI]], [x0]
 ; CHECK: cbnz   [[SCRATCH_RES]], [[LABEL]]
 
diff --git a/llvm/test/CodeGen/AArch64/arm64-atomic.ll b/llvm/test/CodeGen/AArch64/arm64-atomic.ll
index aef79cb386b..b56f91ddd11 100644
--- a/llvm/test/CodeGen/AArch64/arm64-atomic.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-atomic.ll
@@ -35,7 +35,8 @@ define i32 @fetch_and_nand(i32* %p) {
 ; CHECK-LABEL: fetch_and_nand:
 ; CHECK: [[LABEL:.?LBB[0-9]+_[0-9]+]]:
 ; CHECK: ldxr   w[[DEST_REG:[0-9]+]], [x0]
-; CHECK: and    [[SCRATCH2_REG:w[0-9]+]], w[[DEST_REG]], #0xfffffff8
+; CHECK: mvn    [[TMP_REG:w[0-9]+]], w[[DEST_REG]]
+; CHECK: orr    [[SCRATCH2_REG:w[0-9]+]], [[TMP_REG]], #0xfffffff8
 ; CHECK-NOT: stlxr [[SCRATCH2_REG]], [[SCRATCH2_REG]]
 ; CHECK: stlxr   [[SCRATCH_REG:w[0-9]+]], [[SCRATCH2_REG]], [x0]
 ; CHECK: cbnz   [[SCRATCH_REG]], [[LABEL]]
@@ -48,8 +49,9 @@ define i64 @fetch_and_nand_64(i64* %p) {
 ; CHECK-LABEL: fetch_and_nand_64:
 ; CHECK: mov    x[[ADDR:[0-9]+]], x0
 ; CHECK: [[LABEL:.?LBB[0-9]+_[0-9]+]]:
-; CHECK: ldaxr   [[DEST_REG:x[0-9]+]], [x[[ADDR]]]
-; CHECK: and    [[SCRATCH2_REG:x[0-9]+]], [[DEST_REG]], #0xfffffffffffffff8
+; CHECK: ldaxr   x[[DEST_REG:[0-9]+]], [x[[ADDR]]]
+; CHECK: mvn    w[[TMP_REG:[0-9]+]], w[[DEST_REG]]
+; CHECK: orr    [[SCRATCH2_REG:x[0-9]+]], x[[TMP_REG]], #0xfffffffffffffff8
 ; CHECK: stlxr   [[SCRATCH_REG:w[0-9]+]], [[SCRATCH2_REG]], [x[[ADDR]]]
 ; CHECK: cbnz   [[SCRATCH_REG]], [[LABEL]]
 
diff --git a/llvm/test/Transforms/AtomicExpandLoadLinked/ARM/atomic-expansion-v7.ll b/llvm/test/Transforms/AtomicExpandLoadLinked/ARM/atomic-expansion-v7.ll
index f2f5b925163..6a93016fc26 100644
--- a/llvm/test/Transforms/AtomicExpandLoadLinked/ARM/atomic-expansion-v7.ll
+++ b/llvm/test/Transforms/AtomicExpandLoadLinked/ARM/atomic-expansion-v7.ll
@@ -80,8 +80,8 @@ define i16 @test_atomic_nand_i16(i16* %ptr, i16 %nandend) {
 ; CHECK: [[LOOP]]:
 ; CHECK: [[OLDVAL32:%.*]] = call i32 @llvm.arm.ldrex.p0i16(i16* %ptr)
 ; CHECK: [[OLDVAL:%.*]] = trunc i32 [[OLDVAL32]] to i16
-; CHECK: [[NEWVAL_TMP:%.*]] = xor i16 %nandend, -1
-; CHECK: [[NEWVAL:%.*]] = and i16 [[OLDVAL]], [[NEWVAL_TMP]]
+; CHECK: [[NEWVAL_TMP:%.*]] = and i16 [[OLDVAL]], %nandend
+; CHECK: [[NEWVAL:%.*]] = xor i16 [[NEWVAL_TMP]], -1
 ; CHECK: [[NEWVAL32:%.*]] = zext i16 [[NEWVAL]] to i32
 ; CHECK: [[TRYAGAIN:%.*]] = call i32 @llvm.arm.strex.p0i16(i32 [[NEWVAL32]], i16* %ptr)
 ; CHECK: [[TST:%.*]] = icmp ne i32 [[TRYAGAIN]], 0