Index: lib/Analysis/InstructionSimplify.cpp
===================================================================
--- lib/Analysis/InstructionSimplify.cpp
+++ lib/Analysis/InstructionSimplify.cpp
@@ -1127,6 +1127,10 @@
   if (match(Op1, m_Undef()))
     return Op1;
 
+  // X / 1.0 -> X
+  if (match(Op1, m_FPOne()))
+    return Op0;
+
   // 0 / X -> 0
   // Requires that NaNs are off (X could be zero) and signed zeroes are
   // ignored (X could be positive or negative, so the output sign is unknown).
@@ -4093,6 +4097,8 @@
     return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
   case Instruction::FMul:
     return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
+  case Instruction::FDiv:
+    return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
   default:
     return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
   }
Index: test/Transforms/EarlyCSE/instsimplify-fdiv.ll
===================================================================
--- test/Transforms/EarlyCSE/instsimplify-fdiv.ll
+++ test/Transforms/EarlyCSE/instsimplify-fdiv.ll
@@ -0,0 +1,19 @@
+; RUN: opt -O3 -S -mtriple=i686-pc-linux -print-after=early-cse < %s 2>&1 | FileCheck %s
+;
+; Check to make sure divide by 1.0 is simplified in early-cse.
+;
+
+define double @foo(double %x, i32 %n, double %e) #0 {
+entry:
+  %x.addr = alloca double, align 8
+  %n.addr = alloca i32, align 4
+  %e.addr = alloca double, align 8
+  store double %x, double* %x.addr, align 8
+  store i32 %n, i32* %n.addr, align 4
+  store double %e, double* %e.addr, align 8
+  %0 = load double, double* %x.addr, align 8
+  %div = fdiv double %0, 1.000000e+00
+  ret double %div
+}
+
+; CHECK-NOT: fdiv