diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -284,6 +284,14 @@
       return false;
   }
 
+  // Make sure no potentially eflags clobbering phi moves can be inserted in
+  // between.
+  auto HasPhis = [](const BasicBlock *Succ) {
+    return !llvm::empty(Succ->phis());
+  };
+  if (I->isTerminator() && llvm::any_of(successors(I), HasPhis))
+    return false;
+
   CC = TmpCC;
   return true;
 }
diff --git a/llvm/test/CodeGen/X86/pr49587.ll b/llvm/test/CodeGen/X86/pr49587.ll
--- a/llvm/test/CodeGen/X86/pr49587.ll
+++ b/llvm/test/CodeGen/X86/pr49587.ll
@@ -5,10 +5,11 @@
 ; CHECK-LABEL: test:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    subq $1, %rdi
-; CHECK-NEXT:    setb %al
+; CHECK-NEXT:    setb %cl
 ; CHECK-NEXT:    xorl %eax, %eax
+; CHECK-NEXT:    testb $1, %cl
 ; CHECK-NEXT:    movl %eax, {{[-0-9]+}}(%r{{[sb]}}p) # 4-byte Spill
-; CHECK-NEXT:    jb .LBB0_2
+; CHECK-NEXT:    jne .LBB0_2
 ; CHECK-NEXT:  # %bb.1: # %no_overflow
 ; CHECK-NEXT:    movl $1, %eax
 ; CHECK-NEXT:    movl %eax, {{[-0-9]+}}(%r{{[sb]}}p) # 4-byte Spill