diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index 7711a9fd5d92..553e7ebc1fce 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -308,8 +308,16 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
         !isVectorizedStructTy(cast<StructType>(RetTy)))
       return std::nullopt;
 
+    auto getLibcallName = [&] {
+      if (LC == RTLIB::SINCOS_F32)
+        return "sincosf";
+      if (LC == RTLIB::SINCOS_F64)
+        return "sincos";
+      return getTLI()->getLibcallName(LC);
+    };
+
     // Find associated libcall.
-    const char *LCName = getTLI()->getLibcallName(LC);
+    const char *LCName = getLibcallName();
     if (!LCName)
       return std::nullopt;
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index b416c0efbbc4..717d45b4ea39 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2554,7 +2554,19 @@ bool SelectionDAG::expandMultipleResultFPLibCall(
   EVT VT = Node->getValueType(0);
   unsigned NumResults = Node->getNumValues();
 
-  const char *LCName = TLI->getLibcallName(LC);
+  /* Downstream change: #87 (sincos vectorization)*/
+  auto getLibcallName = [&] {
+    if (VT.isVector()) {
+      if (LC == RTLIB::SINCOS_F32)
+        return "sincosf";
+      if (LC == RTLIB::SINCOS_F64)
+        return "sincos";
+    }
+    return TLI->getLibcallName(LC);
+  };
+  /* End downstream change: #87 */
+
+  const char *LCName = getLibcallName();
   if (!LC || !LCName)
     return false;
 
diff --git a/llvm/test/CodeGen/AArch64/veclib-llvm.sincos.ll b/llvm/test/CodeGen/AArch64/veclib-llvm.sincos.ll
index e18ac46165d2..7f40efa34271 100644
--- a/llvm/test/CodeGen/AArch64/veclib-llvm.sincos.ll
+++ b/llvm/test/CodeGen/AArch64/veclib-llvm.sincos.ll
@@ -1,6 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --filter "(bl|ptrue)" --version 5
 ; RUN: llc -mtriple=aarch64-gnu-linux -mattr=+neon,+sve -vector-library=sleefgnuabi < %s | FileCheck %s -check-prefix=SLEEF
 ; RUN: llc -mtriple=aarch64-gnu-linux -mattr=+neon,+sve -vector-library=ArmPL < %s | FileCheck %s -check-prefix=ARMPL
+; Check we expand to a vector library call on aarch64-amazon-linux:
+; RUN: llc -mtriple=aarch64-amazon-linux -mattr=+neon,+sve -vector-library=sleefgnuabi < %s | FileCheck %s -check-prefix=SLEEF
+; RUN: llc -mtriple=aarch64-amazon-linux -mattr=+neon,+sve -vector-library=ArmPL < %s | FileCheck %s -check-prefix=ARMPL
 
 define void @test_sincos_v4f32(<4 x float> %x, ptr noalias %out_sin, ptr noalias %out_cos) {
 ; SLEEF-LABEL: test_sincos_v4f32:
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/sincos.ll b/llvm/test/Transforms/LoopVectorize/AArch64/sincos.ll
index a7e949838f76..bcfa67eb7ab1 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/sincos.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/sincos.ll
@@ -1,8 +1,11 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --filter "(:|sincos|extractvalue|store)" --version 5
 ; RUN: opt -passes=loop-vectorize -mtriple=aarch64-gnu-linux -mcpu=neoverse-v1 -mattr=+sve < %s -S -o - -debug-only=loop-vectorize 2>%t.1 | FileCheck %s --check-prefix=CHECK
 ; RUN: opt -passes=loop-vectorize -mtriple=aarch64-gnu-linux -mcpu=neoverse-v1 -mattr=+sve -vector-library=ArmPL < %s -S -o - -debug-only=loop-vectorize 2>%t.2 | FileCheck %s --check-prefix=CHECK-ARMPL
+; RUN: opt -passes=loop-vectorize -mtriple=aarch64-amazon-linux -mcpu=neoverse-v1 -mattr=+sve -vector-library=ArmPL < %s -S -o - -debug-only=loop-vectorize 2>%t.3 | FileCheck %s --check-prefix=CHECK-ARMPL
 ; RUN: FileCheck --input-file=%t.1 --check-prefix=CHECK-COST %s
 ; RUN: FileCheck --input-file=%t.2 --check-prefix=CHECK-COST-ARMPL %s
+; Check we vectorize the functions with the vector-library on aarch64-amazon-linux:
+; RUN: FileCheck --input-file=%t.3 --check-prefix=CHECK-COST-ARMPL %s
 ; REQUIRES: asserts
 
 ; CHECK-COST-LABEL: sincos_f32