Index: lib/Basic/Targets/AArch64.cpp
===================================================================
--- lib/Basic/Targets/AArch64.cpp
+++ lib/Basic/Targets/AArch64.cpp
@@ -308,7 +308,40 @@
 }
 
 const TargetInfo::GCCRegAlias AArch64TargetInfo::GCCRegAliases[] = {
-    {{"w31"}, "wsp"}, {{"x29"}, "fp"}, {{"x30"}, "lr"}, {{"x31"}, "sp"},
+    {{"w31"}, "wsp"},
+    {{"x31"}, "sp"},
+    // GCC rN registers are aliases of xN registers.
+    {{"r0"}, "x0"},
+    {{"r1"}, "x1"},
+    {{"r2"}, "x2"},
+    {{"r3"}, "x3"},
+    {{"r4"}, "x4"},
+    {{"r5"}, "x5"},
+    {{"r6"}, "x6"},
+    {{"r7"}, "x7"},
+    {{"r8"}, "x8"},
+    {{"r9"}, "x9"},
+    {{"r10"}, "x10"},
+    {{"r11"}, "x11"},
+    {{"r12"}, "x12"},
+    {{"r13"}, "x13"},
+    {{"r14"}, "x14"},
+    {{"r15"}, "x15"},
+    {{"r16"}, "x16"},
+    {{"r17"}, "x17"},
+    {{"r18"}, "x18"},
+    {{"r19"}, "x19"},
+    {{"r20"}, "x20"},
+    {{"r21"}, "x21"},
+    {{"r22"}, "x22"},
+    {{"r23"}, "x23"},
+    {{"r24"}, "x24"},
+    {{"r25"}, "x25"},
+    {{"r26"}, "x26"},
+    {{"r27"}, "x27"},
+    {{"r28"}, "x28"},
+    {{"r29", "x29"}, "fp"},
+    {{"r30", "x30"}, "lr"},
     // The S/D/Q and W/X registers overlap, but aren't really aliases; we
     // don't want to substitute one of these for a different-sized one.
 };
Index: test/CodeGen/aarch64-inline-asm.c
===================================================================
--- test/CodeGen/aarch64-inline-asm.c
+++ test/CodeGen/aarch64-inline-asm.c
@@ -54,3 +54,23 @@
     asm("ldxr %0, %1" : "=r"(val) : "Q"(var));
 // CHECK: call i32 asm "ldxr $0, $1", "=r,*Q"(i64* @var)
 }
+
+void test_gcc_registers(void) {
+    register unsigned long reg0 asm("r0") = 0;
+    register unsigned long reg1 asm("r1") = 1;
+    register unsigned int  reg29 asm("r29") = 2;
+    register unsigned int  reg30 asm("r30") = 3;
+
+    // Test remapping register names in register ... asm("rN") statments.
+    // rN register operands in these two inline assembly lines
+    // should get renamed to valid AArch64 registers.
+    asm volatile("hvc #0" : : "r" (reg0), "r" (reg1));
+    // CHECK: call void asm sideeffect "hvc #0", "{x0},{x1}"
+    asm volatile("hvc #0" : : "r" (reg29), "r" (reg30));
+    // CHECK: call void asm sideeffect "hvc #0", "{fp},{lr}"
+
+    // rN registers when used without register ... asm("rN") syntax
+    // should not be remapped.
+    asm volatile("mov r0, r1\n");
+    // CHECK: call void asm sideeffect "mov r0, r1\0A", ""()
+}