Replace the result usages while legalizing cmpxchg.

We should update the usages to all of the results;
otherwise, we might get assertion failure or SEGV during
the type legalization of ATOMIC_CMP_SWAP_WITH_SUCCESS
with two or more illegal types.

For example, in the following sequence, both i8 and i1
might be illegal in some target, e.g. armv5, mipsel, mips64el,

    %0 = cmpxchg i8* %ptr, i8 %desire, i8 %new monotonic monotonic
    %1 = extractvalue { i8, i1 } %0, 1

Since both i8 and i1 should be legalized, the corresponding
ATOMIC_CMP_SWAP_WITH_SUCCESS dag will be checked/replaced/updated
twice.

If we don't update the usage to *ALL* of the results in the
first round, the DAG for extractvalue might be processed earlier.
The GetPromotedInteger() will result in assertion failure,
because its operand (i.e. the success bit of cmpxchg) is not
promoted beforehand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213569 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

@@ -225,10 +225,9 @@ SDValue DAGTypeLegalizer::PromoteIntRes_AtomicCmpSwap(AtomicSDNode *N,
       N->getOpcode(), SDLoc(N), N->getMemoryVT(), VTs, N->getChain(),
       N->getBasePtr(), Op2, Op3, N->getMemOperand(), N->getSuccessOrdering(),
       N->getFailureOrdering(), N->getSynchScope());
-  // Legalized the chain result - switch anything that used the old chain to
-  // use the new one.
-  unsigned ChainOp = N->getNumValues() - 1;
-  ReplaceValueWith(SDValue(N, ChainOp), Res.getValue(ChainOp));
+  // Update the use to N with the newly created Res.
+  for (unsigned i = 1, NumResults = N->getNumValues(); i < NumResults; ++i)
+    ReplaceValueWith(SDValue(N, i), Res.getValue(i));
   return Res;
 }
 

test/CodeGen/ARM/atomic-cmpxchg.ll

@@ -0,0 +1,50 @@
+; RUN: llc < %s -mtriple=arm-linux-gnueabi -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-ARM
+; RUN: llc < %s -mtriple=thumb-linux-gnueabi -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-THUMB
+
+; RUN: llc < %s -mtriple=armv7-linux-gnueabi -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-ARMV7
+; RUN: llc < %s -mtriple=thumbv7-linux-gnueabi -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-THUMBV7
+
+define zeroext i1 @test_cmpxchg_res_i8(i8* %addr, i8 %desired, i8 zeroext %new) {
+entry:
+  %0 = cmpxchg i8* %addr, i8 %desired, i8 %new monotonic monotonic
+  %1 = extractvalue { i8, i1 } %0, 1
+  ret i1 %1
+}
+
+; CHECK-ARM-LABEL: test_cmpxchg_res_i8
+; CHECK-ARM: bl __sync_val_compare_and_swap_1
+; CHECK-ARM: mov [[REG:r[0-9]+]], #0
+; CHECK-ARM: cmp r0, {{r[0-9]+}}
+; CHECK-ARM: moveq [[REG]], #1
+; CHECK-ARM: mov r0, [[REG]]
+
+; CHECK-THUMB-LABEL: test_cmpxchg_res_i8
+; CHECK-THUMB: bl __sync_val_compare_and_swap_1
+; CHECK-THUMB: mov [[R1:r[0-9]+]], r0
+; CHECK-THUMB: movs r0, #1
+; CHECK-THUMB: movs [[R2:r[0-9]+]], #0
+; CHECK-THUMB: cmp [[R1]], {{r[0-9]+}}
+; CHECK-THU<B: beq
+; CHECK-THUMB: mov r0, [[R2]]
+
+; CHECK-ARMV7-LABEL: test_cmpxchg_res_i8
+; CHECK-ARMV7: ldrexb [[R3:r[0-9]+]], [r0]
+; CHECK-ARMV7: mov [[R1:r[0-9]+]], #0
+; CHECK-ARMV7: cmp [[R3]], {{r[0-9]+}}
+; CHECK-ARMV7: bne
+; CHECK-ARMV7: strexb [[R3]], {{r[0-9]+}}, [{{r[0-9]+}}]
+; CHECK-ARMV7: mov [[R1]], #1
+; CHECK-ARMV7: cmp [[R3]], #0
+; CHECK-ARMV7: bne
+; CHECK-ARMV7: mov r0, [[R1]]
+
+; CHECK-THUMBV7-LABEL: test_cmpxchg_res_i8
+; CHECK-THUMBV7: ldrexb [[R3:r[0-9]+]], [r0]
+; CHECK-THUMBV7: cmp [[R3]], {{r[0-9]+}}
+; CHECK-THUMBV7: movne r0, #0
+; CHECK-THUMBV7: bxne lr
+; CHECK-THUMBV7: strexb [[R3]], {{r[0-9]+}}, [{{r[0-9]+}}]
+; CHECK-THUMBV7: cmp [[R3]], #0
+; CHECK-THUMBV7: itt eq
+; CHECK-THUMBV7: moveq r0, #1
+; CHECK-THUMBV7: bxeq lr

test/CodeGen/Mips/atomic.ll

@@ -8,7 +8,7 @@
 
 ; Keep one big-endian check so that we don't reduce testing, but don't add more
 ; since endianness doesn't affect the body of the atomic operations.
-; RUN: llc -march=mips   --disable-machine-licm -mcpu=mips32 < %s | FileCheck %s -check-prefix=ALL -check-prefix=MIPS32-ANY -check-prefix=CHECK-EB
+; RUN: llc -march=mips   --disable-machine-licm -mcpu=mips32 < %s | FileCheck %s -check-prefix=ALL -check-prefix=MIPS32-ANY -check-prefix=NO-SEB-SEH -check-prefix=CHECK-EB
 
 @x = common global i32 0, align 4
 
@@ -246,6 +246,7 @@ entry:
 ; NO-SEB-SEH:    sra     $2, $[[R17]], 24
 
 ; HAS-SEB-SEH:   seb     $2, $[[R16]]
+
 }
 
 define signext i8 @AtomicCmpSwap8(i8 signext %oldval, i8 signext %newval) nounwind {
@@ -292,6 +293,49 @@ entry:
 ; HAS-SEB-SEH:   seb     $2, $[[R17]]
 }
 
+define i1 @AtomicCmpSwapRes8(i8* %ptr, i8 %oldval, i8 signext %newval) nounwind {
+entry:
+  %0 = cmpxchg i8* %ptr, i8 %oldval, i8 %newval monotonic monotonic
+  %1 = extractvalue { i8, i1 } %0, 1
+  ret i1 %1
+; ALL-LABEL: AtomicCmpSwapRes8
+
+; ALL:           addiu   $[[R1:[0-9]+]], $zero, -4
+; ALL:           and     $[[R2:[0-9]+]], $4, $[[R1]]
+; ALL:           andi    $[[R3:[0-9]+]], $4, 3
+; CHECK-EL:      sll     $[[R5:[0-9]+]], $[[R3]], 3
+; CHECK-EB:      xori    $[[R4:[0-9]+]], $[[R3]], 3
+; CHECK-EB:      sll     $[[R5:[0-9]+]], $[[R4]], 3
+; ALL:           ori     $[[R6:[0-9]+]], $zero, 255
+; ALL:           sllv    $[[R7:[0-9]+]], $[[R6]], $[[R5]]
+; ALL:           nor     $[[R8:[0-9]+]], $zero, $[[R7]]
+; ALL:           andi    $[[R9:[0-9]+]], $5, 255
+; ALL:           sllv    $[[R10:[0-9]+]], $[[R9]], $[[R5]]
+; ALL:           andi    $[[R11:[0-9]+]], $6, 255
+; ALL:           sllv    $[[R12:[0-9]+]], $[[R11]], $[[R5]]
+
+; ALL:       $[[BB0:[A-Z_0-9]+]]:
+; ALL:           ll      $[[R13:[0-9]+]], 0($[[R2]])
+; ALL:           and     $[[R14:[0-9]+]], $[[R13]], $[[R7]]
+; ALL:           bne     $[[R14]], $[[R10]], $[[BB1:[A-Z_0-9]+]]
+
+; ALL:           and     $[[R15:[0-9]+]], $[[R13]], $[[R8]]
+; ALL:           or      $[[R16:[0-9]+]], $[[R15]], $[[R12]]
+; ALL:           sc      $[[R16]], 0($[[R2]])
+; ALL:           beqz    $[[R16]], $[[BB0]]
+
+; ALL:       $[[BB1]]:
+; ALL:           srlv    $[[R17:[0-9]+]], $[[R14]], $[[R5]]
+
+; NO-SEB-SEH:    sll     $[[R18:[0-9]+]], $[[R17]], 24
+; NO-SEB-SEH:    sra     $[[R19:[0-9]+]], $[[R18]], 24
+
+; HAS-SEB-SEH:   seb     $[[R19:[0-9]+]], $[[R17]]
+
+; ALL:           xor     $[[R20:[0-9]+]], $[[R19]], $5
+; ALL:           sltiu   $2, $[[R20]], 1
+}
+
 ; Check one i16 so that we cover the seh sign extend
 @z = common global i16 0, align 1