diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -124,7 +124,7 @@
 
 static cl::opt<bool> EnableQuadwordAtomics(
     "ppc-quadword-atomics",
-    cl::desc("enable quadword lock-free atomic operations"), cl::init(false),
+    cl::desc("enable quadword lock-free atomic operations"), cl::init(true),
     cl::Hidden);
 
 static cl::opt<bool>
@@ -18441,8 +18441,8 @@
 }
 
 bool PPCTargetLowering::shouldInlineQuadwordAtomics() const {
-  // TODO: 16-byte atomic type support for AIX is in progress; we should be able
-  // to inline 16-byte atomic ops on AIX too in the future.
+  // The ability to turn off quadword atomics for AIX is a historical artifact,
+  // i.e., for transition of libatomic on AIX.
   return Subtarget.isPPC64() &&
          (EnableQuadwordAtomics || !Subtarget.getTargetTriple().isOSAIX()) &&
          Subtarget.hasQuadwordAtomics();
diff --git a/llvm/test/CodeGen/PowerPC/atomics-i128-ldst.ll b/llvm/test/CodeGen/PowerPC/atomics-i128-ldst.ll
--- a/llvm/test/CodeGen/PowerPC/atomics-i128-ldst.ll
+++ b/llvm/test/CodeGen/PowerPC/atomics-i128-ldst.ll
@@ -49,15 +49,9 @@
 ;
 ; AIX64-PWR8-LABEL: lq_unordered:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r4, 0
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_load_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lq r4, 0(r3)
+; AIX64-PWR8-NEXT:    mr r3, r4
+; AIX64-PWR8-NEXT:    mr r4, r5
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: lq_unordered:
@@ -124,17 +118,11 @@
 ;
 ; AIX64-PWR8-LABEL: lqx_unordered:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
 ; AIX64-PWR8-NEXT:    sldi r4, r4, 4
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
 ; AIX64-PWR8-NEXT:    add r3, r3, r4
-; AIX64-PWR8-NEXT:    li r4, 0
-; AIX64-PWR8-NEXT:    bl .__atomic_load_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lq r4, 0(r3)
+; AIX64-PWR8-NEXT:    mr r3, r4
+; AIX64-PWR8-NEXT:    mr r4, r5
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: lqx_unordered:
@@ -202,16 +190,11 @@
 ;
 ; AIX64-PWR8-LABEL: lq_big_offset_unordered:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    addis r3, r3, 32
-; AIX64-PWR8-NEXT:    li r4, 0
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_load_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lis r4, 32
+; AIX64-PWR8-NEXT:    add r3, r3, r4
+; AIX64-PWR8-NEXT:    lq r4, 0(r3)
+; AIX64-PWR8-NEXT:    mr r3, r4
+; AIX64-PWR8-NEXT:    mr r4, r5
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: lq_big_offset_unordered:
@@ -271,15 +254,9 @@
 ;
 ; AIX64-PWR8-LABEL: lq_monotonic:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r4, 0
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_load_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lq r4, 0(r3)
+; AIX64-PWR8-NEXT:    mr r3, r4
+; AIX64-PWR8-NEXT:    mr r4, r5
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: lq_monotonic:
@@ -344,15 +321,12 @@
 ;
 ; AIX64-PWR8-LABEL: lq_acquire:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r4, 2
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_load_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lq r4, 0(r3)
+; AIX64-PWR8-NEXT:    cmpd cr7, r5, r5
+; AIX64-PWR8-NEXT:    mr r3, r4
+; AIX64-PWR8-NEXT:    mr r4, r5
+; AIX64-PWR8-NEXT:    bne- cr7, $+4
+; AIX64-PWR8-NEXT:    isync
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: lq_acquire:
@@ -419,15 +393,13 @@
 ;
 ; AIX64-PWR8-LABEL: lq_seqcst:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r4, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_load_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:    lq r4, 0(r3)
+; AIX64-PWR8-NEXT:    cmpd cr7, r5, r5
+; AIX64-PWR8-NEXT:    mr r3, r4
+; AIX64-PWR8-NEXT:    mr r4, r5
+; AIX64-PWR8-NEXT:    bne- cr7, $+4
+; AIX64-PWR8-NEXT:    isync
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: lq_seqcst:
@@ -491,19 +463,9 @@
 ;
 ; AIX64-PWR8-LABEL: stq_unordered:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    mr r6, r4
-; AIX64-PWR8-NEXT:    mr r4, r3
-; AIX64-PWR8-NEXT:    mr r3, r5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    li r6, 0
-; AIX64-PWR8-NEXT:    bl .__atomic_store_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    mr r7, r4
+; AIX64-PWR8-NEXT:    mr r6, r3
+; AIX64-PWR8-NEXT:    stq r6, 0(r5)
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: stq_unordered:
@@ -572,20 +534,11 @@
 ;
 ; AIX64-PWR8-LABEL: stqx_unordered:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    mr r7, r4
-; AIX64-PWR8-NEXT:    mr r4, r3
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    sldi r3, r6, 4
-; AIX64-PWR8-NEXT:    li r6, 0
-; AIX64-PWR8-NEXT:    add r3, r5, r3
-; AIX64-PWR8-NEXT:    mr r5, r7
-; AIX64-PWR8-NEXT:    bl .__atomic_store_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sldi r6, r6, 4
+; AIX64-PWR8-NEXT:    mr r9, r4
+; AIX64-PWR8-NEXT:    mr r8, r3
+; AIX64-PWR8-NEXT:    add r3, r5, r6
+; AIX64-PWR8-NEXT:    stq r8, 0(r3)
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: stqx_unordered:
@@ -656,19 +609,11 @@
 ;
 ; AIX64-PWR8-LABEL: stq_big_offset_unordered:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    mr r6, r4
-; AIX64-PWR8-NEXT:    mr r4, r3
-; AIX64-PWR8-NEXT:    addis r3, r5, 32
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    li r6, 0
-; AIX64-PWR8-NEXT:    bl .__atomic_store_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lis r6, 32
+; AIX64-PWR8-NEXT:    mr r9, r4
+; AIX64-PWR8-NEXT:    mr r8, r3
+; AIX64-PWR8-NEXT:    add r3, r5, r6
+; AIX64-PWR8-NEXT:    stq r8, 0(r3)
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: stq_big_offset_unordered:
@@ -734,19 +679,9 @@
 ;
 ; AIX64-PWR8-LABEL: stq_monotonic:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    mr r6, r4
-; AIX64-PWR8-NEXT:    mr r4, r3
-; AIX64-PWR8-NEXT:    mr r3, r5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    li r6, 0
-; AIX64-PWR8-NEXT:    bl .__atomic_store_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    mr r7, r4
+; AIX64-PWR8-NEXT:    mr r6, r3
+; AIX64-PWR8-NEXT:    stq r6, 0(r5)
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: stq_monotonic:
@@ -812,19 +747,10 @@
 ;
 ; AIX64-PWR8-LABEL: stq_release:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    mr r6, r4
-; AIX64-PWR8-NEXT:    mr r4, r3
-; AIX64-PWR8-NEXT:    mr r3, r5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    li r6, 3
-; AIX64-PWR8-NEXT:    bl .__atomic_store_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r7, r4
+; AIX64-PWR8-NEXT:    mr r6, r3
+; AIX64-PWR8-NEXT:    stq r6, 0(r5)
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: stq_release:
@@ -890,19 +816,10 @@
 ;
 ; AIX64-PWR8-LABEL: stq_seqcst:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    mr r6, r4
-; AIX64-PWR8-NEXT:    mr r4, r3
-; AIX64-PWR8-NEXT:    mr r3, r5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    bl .__atomic_store_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:    mr r7, r4
+; AIX64-PWR8-NEXT:    mr r6, r3
+; AIX64-PWR8-NEXT:    stq r6, 0(r5)
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: stq_seqcst:
diff --git a/llvm/test/CodeGen/PowerPC/atomics-i128.ll b/llvm/test/CodeGen/PowerPC/atomics-i128.ll
--- a/llvm/test/CodeGen/PowerPC/atomics-i128.ll
+++ b/llvm/test/CodeGen/PowerPC/atomics-i128.ll
@@ -73,15 +73,18 @@
 ;
 ; AIX64-PWR8-LABEL: swap:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_exchange_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB0_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    mr r9, r5
+; AIX64-PWR8-NEXT:    mr r8, r4
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB0_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: swap:
@@ -164,15 +167,18 @@
 ;
 ; AIX64-PWR8-LABEL: add:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_fetch_add_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB1_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    addc r9, r5, r7
+; AIX64-PWR8-NEXT:    adde r8, r4, r6
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB1_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: add:
@@ -302,15 +308,18 @@
 ;
 ; AIX64-PWR8-LABEL: sub:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_fetch_sub_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB2_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    subc r9, r7, r5
+; AIX64-PWR8-NEXT:    subfe r8, r4, r6
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB2_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: sub:
@@ -440,15 +449,18 @@
 ;
 ; AIX64-PWR8-LABEL: and:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_fetch_and_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB3_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    and r9, r5, r7
+; AIX64-PWR8-NEXT:    and r8, r4, r6
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB3_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: and:
@@ -578,15 +590,18 @@
 ;
 ; AIX64-PWR8-LABEL: or:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_fetch_or_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB4_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    or r9, r5, r7
+; AIX64-PWR8-NEXT:    or r8, r4, r6
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB4_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: or:
@@ -716,15 +731,18 @@
 ;
 ; AIX64-PWR8-LABEL: xor:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_fetch_xor_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB5_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    xor r9, r5, r7
+; AIX64-PWR8-NEXT:    xor r8, r4, r6
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB5_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: xor:
@@ -854,15 +872,18 @@
 ;
 ; AIX64-PWR8-LABEL: nand:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -112(r1)
-; AIX64-PWR8-NEXT:    li r6, 5
-; AIX64-PWR8-NEXT:    std r0, 128(r1)
-; AIX64-PWR8-NEXT:    bl .__atomic_fetch_nand_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 112
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB6_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r6, 0, r3
+; AIX64-PWR8-NEXT:    nand r9, r5, r7
+; AIX64-PWR8-NEXT:    nand r8, r4, r6
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB6_1
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r6
+; AIX64-PWR8-NEXT:    mr r4, r7
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: nand:
@@ -1017,23 +1038,26 @@
 ;
 ; AIX64-PWR8-LABEL: cas_weak_acquire_acquire:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -128(r1)
-; AIX64-PWR8-NEXT:    std r0, 144(r1)
-; AIX64-PWR8-NEXT:    std r5, 120(r1)
-; AIX64-PWR8-NEXT:    std r4, 112(r1)
-; AIX64-PWR8-NEXT:    addi r4, r1, 112
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    mr r6, r7
-; AIX64-PWR8-NEXT:    li r7, 2
-; AIX64-PWR8-NEXT:    li r8, 2
-; AIX64-PWR8-NEXT:    bl .__atomic_compare_exchange_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    ld r4, 120(r1)
-; AIX64-PWR8-NEXT:    ld r3, 112(r1)
-; AIX64-PWR8-NEXT:    addi r1, r1, 128
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:  L..BB7_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r8, 0, r3
+; AIX64-PWR8-NEXT:    xor r11, r9, r5
+; AIX64-PWR8-NEXT:    xor r10, r8, r4
+; AIX64-PWR8-NEXT:    or. r11, r11, r10
+; AIX64-PWR8-NEXT:    bne cr0, L..BB7_3
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    mr r11, r7
+; AIX64-PWR8-NEXT:    mr r10, r6
+; AIX64-PWR8-NEXT:    stqcx. r10, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB7_1
+; AIX64-PWR8-NEXT:    b L..BB7_4
+; AIX64-PWR8-NEXT:  L..BB7_3: # %entry
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:  L..BB7_4: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r8
+; AIX64-PWR8-NEXT:    mr r4, r9
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: cas_weak_acquire_acquire:
@@ -1148,23 +1172,26 @@
 ;
 ; AIX64-PWR8-LABEL: cas_weak_release_monotonic:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -128(r1)
-; AIX64-PWR8-NEXT:    std r0, 144(r1)
-; AIX64-PWR8-NEXT:    std r5, 120(r1)
-; AIX64-PWR8-NEXT:    std r4, 112(r1)
-; AIX64-PWR8-NEXT:    addi r4, r1, 112
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    mr r6, r7
-; AIX64-PWR8-NEXT:    li r7, 3
-; AIX64-PWR8-NEXT:    li r8, 0
-; AIX64-PWR8-NEXT:    bl .__atomic_compare_exchange_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    ld r4, 120(r1)
-; AIX64-PWR8-NEXT:    ld r3, 112(r1)
-; AIX64-PWR8-NEXT:    addi r1, r1, 128
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:  L..BB8_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r8, 0, r3
+; AIX64-PWR8-NEXT:    xor r11, r9, r5
+; AIX64-PWR8-NEXT:    xor r10, r8, r4
+; AIX64-PWR8-NEXT:    or. r11, r11, r10
+; AIX64-PWR8-NEXT:    bne cr0, L..BB8_3
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    mr r11, r7
+; AIX64-PWR8-NEXT:    mr r10, r6
+; AIX64-PWR8-NEXT:    stqcx. r10, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB8_1
+; AIX64-PWR8-NEXT:    b L..BB8_4
+; AIX64-PWR8-NEXT:  L..BB8_3: # %entry
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:  L..BB8_4: # %entry
+; AIX64-PWR8-NEXT:    mr r3, r8
+; AIX64-PWR8-NEXT:    mr r4, r9
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: cas_weak_release_monotonic:
@@ -1281,23 +1308,27 @@
 ;
 ; AIX64-PWR8-LABEL: cas_sc_sc:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -128(r1)
-; AIX64-PWR8-NEXT:    std r0, 144(r1)
-; AIX64-PWR8-NEXT:    std r5, 120(r1)
-; AIX64-PWR8-NEXT:    std r4, 112(r1)
-; AIX64-PWR8-NEXT:    addi r4, r1, 112
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    mr r6, r7
-; AIX64-PWR8-NEXT:    li r7, 5
-; AIX64-PWR8-NEXT:    li r8, 5
-; AIX64-PWR8-NEXT:    bl .__atomic_compare_exchange_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    ld r4, 120(r1)
-; AIX64-PWR8-NEXT:    ld r3, 112(r1)
-; AIX64-PWR8-NEXT:    addi r1, r1, 128
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    sync
+; AIX64-PWR8-NEXT:  L..BB9_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r8, 0, r3
+; AIX64-PWR8-NEXT:    xor r11, r9, r5
+; AIX64-PWR8-NEXT:    xor r10, r8, r4
+; AIX64-PWR8-NEXT:    or. r11, r11, r10
+; AIX64-PWR8-NEXT:    bne cr0, L..BB9_3
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    mr r11, r7
+; AIX64-PWR8-NEXT:    mr r10, r6
+; AIX64-PWR8-NEXT:    stqcx. r10, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB9_1
+; AIX64-PWR8-NEXT:    b L..BB9_4
+; AIX64-PWR8-NEXT:  L..BB9_3: # %entry
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:  L..BB9_4: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r8
+; AIX64-PWR8-NEXT:    mr r4, r9
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: cas_sc_sc:
@@ -1414,23 +1445,27 @@
 ;
 ; AIX64-PWR8-LABEL: cas_acqrel_acquire:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -128(r1)
-; AIX64-PWR8-NEXT:    std r0, 144(r1)
-; AIX64-PWR8-NEXT:    std r5, 120(r1)
-; AIX64-PWR8-NEXT:    std r4, 112(r1)
-; AIX64-PWR8-NEXT:    addi r4, r1, 112
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    mr r6, r7
-; AIX64-PWR8-NEXT:    li r7, 4
-; AIX64-PWR8-NEXT:    li r8, 2
-; AIX64-PWR8-NEXT:    bl .__atomic_compare_exchange_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    ld r4, 120(r1)
-; AIX64-PWR8-NEXT:    ld r3, 112(r1)
-; AIX64-PWR8-NEXT:    addi r1, r1, 128
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:  L..BB10_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r8, 0, r3
+; AIX64-PWR8-NEXT:    xor r11, r9, r5
+; AIX64-PWR8-NEXT:    xor r10, r8, r4
+; AIX64-PWR8-NEXT:    or. r11, r11, r10
+; AIX64-PWR8-NEXT:    bne cr0, L..BB10_3
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    mr r11, r7
+; AIX64-PWR8-NEXT:    mr r10, r6
+; AIX64-PWR8-NEXT:    stqcx. r10, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB10_1
+; AIX64-PWR8-NEXT:    b L..BB10_4
+; AIX64-PWR8-NEXT:  L..BB10_3: # %entry
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:  L..BB10_4: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    mr r3, r8
+; AIX64-PWR8-NEXT:    mr r4, r9
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: cas_acqrel_acquire:
@@ -1551,21 +1586,30 @@
 ;
 ; AIX64-PWR8-LABEL: cas_acqrel_acquire_check_succ:
 ; AIX64-PWR8:       # %bb.0: # %entry
-; AIX64-PWR8-NEXT:    mflr r0
-; AIX64-PWR8-NEXT:    stdu r1, -128(r1)
-; AIX64-PWR8-NEXT:    std r0, 144(r1)
-; AIX64-PWR8-NEXT:    std r5, 120(r1)
-; AIX64-PWR8-NEXT:    std r4, 112(r1)
-; AIX64-PWR8-NEXT:    addi r4, r1, 112
-; AIX64-PWR8-NEXT:    mr r5, r6
-; AIX64-PWR8-NEXT:    mr r6, r7
-; AIX64-PWR8-NEXT:    li r7, 4
-; AIX64-PWR8-NEXT:    li r8, 2
-; AIX64-PWR8-NEXT:    bl .__atomic_compare_exchange_16[PR]
-; AIX64-PWR8-NEXT:    nop
-; AIX64-PWR8-NEXT:    addi r1, r1, 128
-; AIX64-PWR8-NEXT:    ld r0, 16(r1)
-; AIX64-PWR8-NEXT:    mtlr r0
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:  L..BB11_1: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    lqarx r8, 0, r3
+; AIX64-PWR8-NEXT:    xor r11, r9, r5
+; AIX64-PWR8-NEXT:    xor r10, r8, r4
+; AIX64-PWR8-NEXT:    or. r11, r11, r10
+; AIX64-PWR8-NEXT:    bne cr0, L..BB11_3
+; AIX64-PWR8-NEXT:  # %bb.2: # %entry
+; AIX64-PWR8-NEXT:    #
+; AIX64-PWR8-NEXT:    mr r11, r7
+; AIX64-PWR8-NEXT:    mr r10, r6
+; AIX64-PWR8-NEXT:    stqcx. r10, 0, r3
+; AIX64-PWR8-NEXT:    bne cr0, L..BB11_1
+; AIX64-PWR8-NEXT:    b L..BB11_4
+; AIX64-PWR8-NEXT:  L..BB11_3: # %entry
+; AIX64-PWR8-NEXT:    stqcx. r8, 0, r3
+; AIX64-PWR8-NEXT:  L..BB11_4: # %entry
+; AIX64-PWR8-NEXT:    lwsync
+; AIX64-PWR8-NEXT:    xor r3, r4, r8
+; AIX64-PWR8-NEXT:    xor r4, r5, r9
+; AIX64-PWR8-NEXT:    or r3, r4, r3
+; AIX64-PWR8-NEXT:    cntlzd r3, r3
+; AIX64-PWR8-NEXT:    rldicl r3, r3, 58, 63
 ; AIX64-PWR8-NEXT:    blr
 ;
 ; PPC-PWR8-LABEL: cas_acqrel_acquire_check_succ: