Fixups

Author: MacDue

llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

@@ -2353,29 +2353,23 @@ void SelectionDAGLegalize::ExpandSinCosLibCall(
   Type *Ty = VT.getTypeForEVT(*DAG.getContext());
   RTLIB::Libcall LC = RTLIB::getFSINCOS(VT);
 
-  // Find users of the node that store the results. The destination pointers
-  // can be used instead of creating stack allocations.
+  // Find users of the node that store the results (and share input chains). The
+  // destination pointers can be used instead of creating stack allocations.
+  SDValue StoresInChain{};
   std::array<StoreSDNode *, 2> ResultStores = {nullptr};
   for (SDNode *User : Node->uses()) {
     if (!ISD::isNormalStore(User))
       continue;
     auto *ST = cast<StoreSDNode>(User);
     if (!ST->isSimple() || ST->getAddressSpace() != 0 ||
-        ST->getAlign() < DAG.getDataLayout().getABITypeAlign(Ty))
+        ST->getAlign() < DAG.getDataLayout().getABITypeAlign(Ty) ||
+        (StoresInChain && ST->getChain() != StoresInChain) ||
+        Node->isPredecessorOf(ST->getChain().getNode()))
       continue;
     ResultStores[ST->getValue().getResNo()] = ST;
+    StoresInChain = ST->getChain();
   }
 
-  // Collect input chains (and avoid chains referring to one of the stores).
-  SmallVector<SDValue, 2> InChains;
-  for (auto [ResNum, ST] : llvm::enumerate(ResultStores)) {
-    unsigned OtherResNum = ResNum == 0 ? 1 : 0;
-    if (ST && ST->getChain().getNode() != ResultStores[OtherResNum])
-      InChains.push_back(ST->getChain());
-  }
-  if (InChains.empty())
-    InChains.push_back(DAG.getEntryNode());
-
   TargetLowering::ArgListTy Args;
   TargetLowering::ArgListEntry Entry{};
 
@@ -2395,9 +2389,7 @@ void SelectionDAGLegalize::ExpandSinCosLibCall(
   }
 
   SDLoc DL(Node);
-
-  // Combine any input chains from the stores.
-  SDValue InChain = DAG.getTokenFactor(DL, InChains);
+  SDValue InChain = StoresInChain ? StoresInChain : DAG.getEntryNode();
   SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
                                          TLI.getPointerTy(DAG.getDataLayout()));
   TargetLowering::CallLoweringInfo CLI(DAG);

llvm/test/CodeGen/AArch64/sincos-stack-slots.ll

@@ -23,7 +23,7 @@ entry:
   ret { float, float } %ret_1
 }
 
-define void @sincos_f32_ptr_return(float %x, ptr %out_sin, ptr %out_cos) {
+define void @sincos_f32_ptr_return(float %x, ptr noalias %out_sin, ptr noalias %out_cos) {
 ; CHECK-LABEL: sincos_f32_ptr_return:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
@@ -81,7 +81,7 @@ entry:
   ret { double, double } %ret_1
 }
 
-define void @sincos_f64_ptr_return(double %x, ptr %out_sin, ptr %out_cos) {
+define void @sincos_f64_ptr_return(double %x, ptr noalias %out_sin, ptr noalias %out_cos) {
 ; CHECK-LABEL: sincos_f64_ptr_return:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
@@ -116,8 +116,55 @@ entry:
   ret double %cos
 }
 
+; Here %out_sin and %out_cos may alias so we can't replace both stores with the
+; call to sincosf (as the order of stores in sincosf is not defined).
+define void @sincos_may_alias(float %x, ptr %out_sin, ptr %out_cos) {
+; CHECK-LABEL: sincos_may_alias:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    sub sp, sp, #32
+; CHECK-NEXT:    stp x30, x19, [sp, #16] // 16-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 32
+; CHECK-NEXT:    .cfi_offset w19, -8
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    mov x19, x1
+; CHECK-NEXT:    add x1, sp, #12
+; CHECK-NEXT:    bl sincosf
+; CHECK-NEXT:    ldr s0, [sp, #12]
+; CHECK-NEXT:    str s0, [x19]
+; CHECK-NEXT:    ldp x30, x19, [sp, #16] // 16-byte Folded Reload
+; CHECK-NEXT:    add sp, sp, #32
+; CHECK-NEXT:    ret
+entry:
+  %sin = tail call float @llvm.sin.f32(float %x)
+  %cos = tail call float @llvm.cos.f32(float %x)
+  store float %sin, ptr %out_sin, align 4
+  store float %cos, ptr %out_cos, align 4
+  ret void
+}
+
+; Here %out is used for both sin and cos (with the final value stored being cos).
+define float @sincos_multiple_uses(float %x, ptr %out) {
+; CHECK-LABEL: sincos_multiple_uses:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    mov x1, x0
+; CHECK-NEXT:    add x0, sp, #12
+; CHECK-NEXT:    bl sincosf
+; CHECK-NEXT:    ldr s0, [sp, #12]
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+  %sin = call float @llvm.sin.f32(float %x)
+  store float %sin, ptr %out, align 4
+  %reload = load float, ptr %out, align 4
+  %cos = call float @llvm.cos.f32(float %x)
+  store float %cos, ptr %out, align 4
+  ret float %reload
+}
+
 ; Negative test. We can't fold volatile stores into the library call.
-define void @sincos_volatile_result_stores(float %x, ptr %out_sin, ptr %out_cos) {
+define void @sincos_volatile_result_stores(float %x, ptr noalias %out_sin, ptr noalias %out_cos) {
 ; CHECK-LABEL: sincos_volatile_result_stores:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    str x30, [sp, #-32]! // 8-byte Folded Spill
@@ -146,7 +193,7 @@ entry:
 }
 
 ; Negative test. We can't fold atomic stores into the library call.
-define void @sincos_atomic_result_stores(float %x, ptr %out_sin, ptr %out_cos) {
+define void @sincos_atomic_result_stores(float %x, ptr noalias %out_sin, ptr noalias %out_cos) {
 ; CHECK-LABEL: sincos_atomic_result_stores:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    str x30, [sp, #-32]! // 8-byte Folded Spill
@@ -176,7 +223,7 @@ entry:
 }
 
 ; Negative test. We can't fold misaligned stores into the library call.
-define void @sincos_misaligned_result_stores(double %x, ptr %out_sin, ptr %out_cos) {
+define void @sincos_misaligned_result_stores(double %x, ptr noalias %out_sin, ptr noalias %out_cos) {
 ; CHECK-LABEL: sincos_misaligned_result_stores:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    sub sp, sp, #48