diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -4350,9 +4350,6 @@
         // Cannot do anything for any other EFLAG changes.
         return false;
       }
-
-      if (Inst.readsRegister(X86::EFLAGS, TRI))
-        return false;
     }
 
     if (MI || Sub)
diff --git a/llvm/test/CodeGen/X86/optimize-compare.mir b/llvm/test/CodeGen/X86/optimize-compare.mir
--- a/llvm/test/CodeGen/X86/optimize-compare.mir
+++ b/llvm/test/CodeGen/X86/optimize-compare.mir
@@ -151,3 +151,23 @@
     CMP32rr %1, %0, implicit-def $eflags
     $bl = SETCCr 3, implicit $eflags
 ...
+---
+name: opt_redundant_flags_2
+body: |
+  bb.0:
+    ; CHECK-LABEL: name: opt_redundant_flags_2
+    ; CHECK: [[COPY:%[0-9]+]]:gr32 = COPY $esi
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:gr32 = COPY $edi
+    ; CHECK-NEXT: [[SUB32rr:%[0-9]+]]:gr32 = SUB32rr [[COPY]], [[COPY1]], implicit-def $eflags
+    ; CHECK-NEXT: $cl = SETCCr 2, implicit $eflags
+    ; CHECK-NEXT: $eax = COPY [[SUB32rr]]
+    ; CHECK-NEXT: $bl = SETCCr 2, implicit $eflags
+    %0:gr32 = COPY $esi
+    %1:gr32 = COPY $edi
+    %2:gr32 = SUB32rr %0, %1, implicit-def $eflags
+    ; an extra eflags reader shouldn't stop optimization.
+    $cl = SETCCr 2, implicit $eflags
+    $eax = COPY %2
+    CMP32rr %0, %1, implicit-def $eflags
+    $bl = SETCCr 2, implicit $eflags
+...