diff --git a/llvm/lib/FileCheck/FileCheck.cpp b/llvm/lib/FileCheck/FileCheck.cpp
--- a/llvm/lib/FileCheck/FileCheck.cpp
+++ b/llvm/lib/FileCheck/FileCheck.cpp
@@ -1007,8 +1007,9 @@
     // brackets. They also accept a combined form which sets a numeric variable
     // to the evaluation of an expression. Both string and numeric variable
     // names must satisfy the regular expression "[a-zA-Z_][0-9a-zA-Z_]*" to be
-    // valid, as this helps catch some common errors.
-    if (PatternStr.startswith("[[")) {
+    // valid, as this helps catch some common errors. If there are extra '['s
+    // before the "[[", treat them literally.
+    if (PatternStr.startswith("[[") && !PatternStr.startswith("[[[")) {
       StringRef UnparsedPatternStr = PatternStr.substr(2);
       // Find the closing bracket pair ending the match.  End is going to be an
       // offset relative to the beginning of the match string.
@@ -1183,12 +1184,14 @@
           Substitutions.push_back(Substitution);
         }
       }
+
+      continue;
     }
 
     // Handle fixed string matches.
     // Find the end, which is the start of the next regex.
-    size_t FixedMatchEnd = PatternStr.find("{{");
-    FixedMatchEnd = std::min(FixedMatchEnd, PatternStr.find("[["));
+    size_t FixedMatchEnd =
+        std::min(PatternStr.find("{{", 1), PatternStr.find("[[", 1));
     RegExStr += Regex::escape(PatternStr.substr(0, FixedMatchEnd));
     PatternStr = PatternStr.substr(FixedMatchEnd);
   }
diff --git a/llvm/test/CodeGen/Mips/msa/3r-s.ll b/llvm/test/CodeGen/Mips/msa/3r-s.ll
--- a/llvm/test/CodeGen/Mips/msa/3r-s.ll
+++ b/llvm/test/CodeGen/Mips/msa/3r-s.ll
@@ -28,7 +28,7 @@
 ; CHECK-DAG: ld.b [[WD:\$w[0-9]+]], 0([[R1]])
 ; CHECK-DAG: ld.b [[WS:\$w[0-9]+]], 0([[R2]])
 ; CHECK-DAG: lw [[RT:\$[0-9]+]], 0([[R3]])
-; CHECK-DAG: sld.b [[WD]], [[WS]]{{\[}}[[RT]]{{\]}}
+; CHECK-DAG: sld.b [[WD]], [[WS]][[[RT]]]
 ; CHECK-DAG: st.b [[WD]]
 ; CHECK: .size llvm_mips_sld_b_test
 ;
@@ -56,7 +56,7 @@
 ; CHECK-DAG: ld.h [[WD:\$w[0-9]+]], 0([[R1]])
 ; CHECK-DAG: ld.h [[WS:\$w[0-9]+]], 0([[R2]])
 ; CHECK-DAG: lw [[RT:\$[0-9]+]], 0([[R3]])
-; CHECK-DAG: sld.h [[WD]], [[WS]]{{\[}}[[RT]]{{\]}}
+; CHECK-DAG: sld.h [[WD]], [[WS]][[[RT]]]
 ; CHECK-DAG: st.h [[WD]]
 ; CHECK: .size llvm_mips_sld_h_test
 ;
@@ -84,7 +84,7 @@
 ; CHECK-DAG: ld.w [[WD:\$w[0-9]+]], 0([[R1]])
 ; CHECK-DAG: ld.w [[WS:\$w[0-9]+]], 0([[R2]])
 ; CHECK-DAG: lw [[RT:\$[0-9]+]], 0([[R3]])
-; CHECK-DAG: sld.w [[WD]], [[WS]]{{\[}}[[RT]]{{\]}}
+; CHECK-DAG: sld.w [[WD]], [[WS]][[[RT]]]
 ; CHECK-DAG: st.w [[WD]]
 ; CHECK: .size llvm_mips_sld_w_test
 ;
@@ -112,7 +112,7 @@
 ; CHECK-DAG: ld.d [[WD:\$w[0-9]+]], 0([[R1]])
 ; CHECK-DAG: ld.d [[WS:\$w[0-9]+]], 0([[R2]])
 ; CHECK-DAG: lw [[RT:\$[0-9]+]], 0([[R3]])
-; CHECK-DAG: sld.d [[WD]], [[WS]]{{\[}}[[RT]]{{\]}}
+; CHECK-DAG: sld.d [[WD]], [[WS]][[[RT]]]
 ; CHECK-DAG: st.d [[WD]]
 ; CHECK: .size llvm_mips_sld_d_test
 ;
diff --git a/llvm/test/CodeGen/Mips/msa/basic_operations_float.ll b/llvm/test/CodeGen/Mips/msa/basic_operations_float.ll
--- a/llvm/test/CodeGen/Mips/msa/basic_operations_float.ll
+++ b/llvm/test/CodeGen/Mips/msa/basic_operations_float.ll
@@ -196,7 +196,7 @@
   ; ALL-DAG: lw [[IDX:\$[0-9]+]], 0([[PTR_I]])
 
   %4 = extractelement <4 x float> %2, i32 %3
-  ; ALL-DAG: splat.w $w0, [[R1]]{{\[}}[[IDX]]]
+  ; ALL-DAG: splat.w $w0, [[R1]][[[IDX]]]
 
   ret float %4
 }
@@ -262,7 +262,7 @@
   ; ALL-DAG: lw [[IDX:\$[0-9]+]], 0([[PTR_I]])
 
   %4 = extractelement <2 x double> %2, i32 %3
-  ; ALL-DAG: splat.d $w0, [[R1]]{{\[}}[[IDX]]]
+  ; ALL-DAG: splat.d $w0, [[R1]][[[IDX]]]
 
   ret double %4
 }
@@ -317,10 +317,10 @@
   %3 = insertelement <4 x float> %1, float %a, i32 %2
   ; float argument passed in $f12
   ; ALL-DAG: sll [[BIDX:\$[0-9]+]], [[IDX]], 2
-  ; ALL-DAG: sld.b [[R1]], [[R1]]{{\[}}[[BIDX]]]
+  ; ALL-DAG: sld.b [[R1]], [[R1]][[[BIDX]]]
   ; ALL-DAG: insve.w [[R1]][0], $w12[0]
   ; ALL-DAG: neg [[NIDX:\$[0-9]+]], [[BIDX]]
-  ; ALL-DAG: sld.b [[R1]], [[R1]]{{\[}}[[NIDX]]]
+  ; ALL-DAG: sld.b [[R1]], [[R1]][[[NIDX]]]
 
   store <4 x float> %3, <4 x float>* @v4f32
   ; ALL-DAG: st.w [[R1]]
@@ -346,10 +346,10 @@
   %3 = insertelement <2 x double> %1, double %a, i32 %2
   ; double argument passed in $f12
   ; ALL-DAG: sll [[BIDX:\$[0-9]+]], [[IDX]], 3
-  ; ALL-DAG: sld.b [[R1]], [[R1]]{{\[}}[[BIDX]]]
+  ; ALL-DAG: sld.b [[R1]], [[R1]][[[BIDX]]]
   ; ALL-DAG: insve.d [[R1]][0], $w12[0]
   ; ALL-DAG: neg [[NIDX:\$[0-9]+]], [[BIDX]]
-  ; ALL-DAG: sld.b [[R1]], [[R1]]{{\[}}[[NIDX]]]
+  ; ALL-DAG: sld.b [[R1]], [[R1]][[[NIDX]]]
 
   store <2 x double> %3, <2 x double>* @v2f64
   ; ALL-DAG: st.d [[R1]]
diff --git a/llvm/test/FileCheck/regex-brackets.txt b/llvm/test/FileCheck/regex-brackets.txt
--- a/llvm/test/FileCheck/regex-brackets.txt
+++ b/llvm/test/FileCheck/regex-brackets.txt
@@ -2,6 +2,7 @@
 
 op r1
 op r2, [x r1]
+op r3, [r1]
 ; CHECK:        op [[REG:r[0-9]]]
 ; CHECK:        op [[REG2:r[0-9]]], [x [[REG]]]
-
+; CHECK:        op [[REG3:r[0-9]]], [[[REG]]]