diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -2559,7 +2559,7 @@
         ArgElemTypes.push_back(nullptr);
         if (!Constraints.empty())
           Constraints += ',';
-        Constraints += 'X';
+        Constraints += 'i';
       }
       Fallthrough = createBasicBlock("asm.fallthrough");
     }
diff --git a/clang/test/CodeGen/asm-goto.c b/clang/test/CodeGen/asm-goto.c
--- a/clang/test/CodeGen/asm-goto.c
+++ b/clang/test/CodeGen/asm-goto.c
@@ -55,14 +55,14 @@
 
 int test4(int out1, int out2) {
   // CHECK-LABEL: define{{.*}} i32 @test4(
-  // CHECK: callbr { i32, i32 } asm sideeffect "jne ${3:l}", "={si},={di},r,X,X,0,1
+  // CHECK: callbr { i32, i32 } asm sideeffect "jne ${3:l}", "={si},={di},r,i,i,0,1
   // CHECK: to label %asm.fallthrough [label %label_true, label %loop]
   // CHECK-LABEL: asm.fallthrough:
   if (out1 < out2)
     asm volatile goto("jne %l3" : "+S"(out1), "+D"(out2) : "r"(out1) :: label_true, loop);
   else
     asm volatile goto("jne %l5" : "+S"(out1), "+D"(out2) : "r"(out1), "r"(out2) :: label_true, loop);
-  // CHECK: callbr { i32, i32 } asm sideeffect "jne ${5:l}", "={si},={di},r,r,X,X,0,1
+  // CHECK: callbr { i32, i32 } asm sideeffect "jne ${5:l}", "={si},={di},r,r,i,i,0,1
   // CHECK: to label %asm.fallthrough2 [label %label_true, label %loop]
   // CHECK-LABEL: asm.fallthrough2:
   return out1 + out2;
@@ -74,7 +74,7 @@
 
 int test5(int addr, int size, int limit) {
   // CHECK-LABEL: define{{.*}} i32 @test5(
-  // CHECK: callbr i32 asm "add $1,$0 ; jc ${3:l} ; cmp $2,$0 ; ja ${3:l} ; ", "=r,imr,imr,X,0
+  // CHECK: callbr i32 asm "add $1,$0 ; jc ${3:l} ; cmp $2,$0 ; ja ${3:l} ; ", "=r,imr,imr,i,0
   // CHECK: to label %asm.fallthrough [label %t_err]
   // CHECK-LABEL: asm.fallthrough:
   asm goto(
@@ -92,7 +92,7 @@
 
 int test6(int out1) {
   // CHECK-LABEL: define{{.*}} i32 @test6(
-  // CHECK: callbr i32 asm sideeffect "testl $0, $0; testl $1, $1; jne ${2:l}", "={si},r,X,X,0,{{.*}} i8* blockaddress(@test6, %label_true), i8* blockaddress(@test6, %landing)
+  // CHECK: callbr i32 asm sideeffect "testl $0, $0; testl $1, $1; jne ${2:l}", "={si},r,i,i,0,{{.*}} i8* blockaddress(@test6, %label_true), i8* blockaddress(@test6, %landing)
   // CHECK: to label %asm.fallthrough [label %label_true, label %landing]
   // CHECK-LABEL: asm.fallthrough:
   // CHECK-LABEL: landing:
diff --git a/clang/test/CodeGen/asm.c b/clang/test/CodeGen/asm.c
--- a/clang/test/CodeGen/asm.c
+++ b/clang/test/CodeGen/asm.c
@@ -267,7 +267,7 @@
 int t32(int cond)
 {
   asm goto("testl %0, %0; jne %l1;" :: "r"(cond)::label_true, loop);
-  // CHECK: callbr void asm sideeffect "testl $0, $0; jne ${1:l};", "r,X,X,~{dirflag},~{fpsr},~{flags}"(i32 %0, i8* blockaddress(@t32, %label_true), i8* blockaddress(@t32, %loop)) #1
+  // CHECK: callbr void asm sideeffect "testl $0, $0; jne ${1:l};", "r,i,i,~{dirflag},~{fpsr},~{flags}"(i32 %0, i8* blockaddress(@t32, %label_true), i8* blockaddress(@t32, %loop)) #1
   return 0;
 loop:
   return 0;
diff --git a/clang/test/Modules/asm-goto.c b/clang/test/Modules/asm-goto.c
--- a/clang/test/Modules/asm-goto.c
+++ b/clang/test/Modules/asm-goto.c
@@ -4,7 +4,7 @@
 #include "a.h"
 
 // CHECK-LABEL: define {{.*}} @foo(
-// CHECK: callbr {{.*}} "=r,X{{.*}} blockaddress(@foo, %indirect))
+// CHECK: callbr {{.*}} "=r,i{{.*}} blockaddress(@foo, %indirect))
 // CHECK-NEXT: to label %asm.fallthrough [label %indirect]
 
 int bar(void) {