3 files changed, 16 insertions, 2 deletions
diff --git a/js/src/jit/arm/Assembler-arm.cpp b/js/src/jit/arm/Assembler-arm.cpp
index 1e20da1c8..b231128c5 100644
--- a/js/src/jit/arm/Assembler-arm.cpp
+++ b/js/src/jit/arm/Assembler-arm.cpp
@@ -171,6 +171,18 @@ ABIArgGenerator::next(MIRType type)
     return softNext(type);
 }
 
+bool
+js::jit::IsUnaligned(const wasm::MemoryAccessDesc& access)
+{
+    if (!access.align())
+        return false;
+
+    if (access.type() == Scalar::Float64 && access.align() >= 4)
+        return false;
+
+    return access.align() < access.byteSize();
+}
+
 // Encode a standard register when it is being used as src1, the dest, and an
 // extra register. These should never be called with an InvalidReg.
 uint32_t
diff --git a/js/src/jit/arm/Assembler-arm.h b/js/src/jit/arm/Assembler-arm.h
index 8bb754a50..ecfb83b42 100644
--- a/js/src/jit/arm/Assembler-arm.h
+++ b/js/src/jit/arm/Assembler-arm.h
@@ -108,6 +108,8 @@ class ABIArgGenerator
     uint32_t stackBytesConsumedSoFar() const { return stackOffset_; }
 };
 
+bool IsUnaligned(const wasm::MemoryAccessDesc& access);
+
 static constexpr Register ABINonArgReg0 = r4;
 static constexpr Register ABINonArgReg1 = r5;
 static constexpr Register ABINonArgReg2 = r6;
diff --git a/js/src/jit/arm/Lowering-arm.cpp b/js/src/jit/arm/Lowering-arm.cpp
index c26680116..b9440816a 100644
--- a/js/src/jit/arm/Lowering-arm.cpp
+++ b/js/src/jit/arm/Lowering-arm.cpp
@@ -613,7 +613,7 @@ LIRGeneratorARM::visitWasmLoad(MWasmLoad* ins)
 
     LAllocation ptr = useRegisterAtStart(base);
 
-    if (ins->access().isUnaligned()) {
+    if (IsUnaligned(ins->access())) {
         // Unaligned access expected! Revert to a byte load.
         LDefinition ptrCopy = tempCopy(base, 0);
 
@@ -662,7 +662,7 @@ LIRGeneratorARM::visitWasmStore(MWasmStore* ins)
 
     LAllocation ptr = useRegisterAtStart(base);
 
-    if (ins->access().isUnaligned()) {
+    if (IsUnaligned(ins->access())) {
         // Unaligned access expected! Revert to a byte store.
         LDefinition ptrCopy = tempCopy(base, 0);