commit 5d90f886bc022e7c9144a0ef08ea7ccde7e66030
Author: Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue Mar 17 10:51:21 2020 -0700

    [clang][AArch64] readd support for 'p' inline asm constraint
    
    Summary:
    Was accidentally removed by commit af64948e2a05 when it overrode
    TargetInfo::convertConstraint.
    
    Fixes: pr/45225
    
    Reviewers: eli.friedman, sdesmalen
    
    Reviewed By: sdesmalen
    
    Subscribers: echristo, sdesmalen, kristof.beyls, cfe-commits, kmclaughlin, srhines
    
    Tags: #clang
    
    Differential Revision: https://reviews.llvm.org/D76297

diff --git a/clang/lib/Basic/Targets/AArch64.h b/clang/lib/Basic/Targets/AArch64.h
index befbf693ad8..41970e5d716 100644
--- a/clang/lib/Basic/Targets/AArch64.h
+++ b/clang/lib/Basic/Targets/AArch64.h
@@ -96,7 +96,7 @@ public:
       Constraint += 2;
       break;
     default:
-      R = std::string(1, *Constraint);
+      R = TargetInfo::convertConstraint(Constraint);
       break;
     }
     return R;
diff --git a/clang/test/CodeGen/inline-asm-p-constraint.c b/clang/test/CodeGen/inline-asm-p-constraint.c
new file mode 100644
index 00000000000..70db78bc649
--- /dev/null
+++ b/clang/test/CodeGen/inline-asm-p-constraint.c
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -emit-llvm %s -o - -triple aarch64-linux-gnu | FileCheck %s
+void foo(void* ptr) {
+  asm volatile("prfm pldl1keep, %a0\n" : : "p" (ptr));
+  // CHECK:     call void asm sideeffect "prfm pldl1keep, ${0:a}\0A", "r"(i8* %0)
+  // CHECK-NOT: call void asm sideeffect "prfm pldl1keep, ${0:a}\0A", "p"(i8* %0)
+}