[SimplifyLibCalls] Transform log(exp2(y)) to y*log(2) under fast-math.

llvm-svn: 254317
diff --git a/llvm/test/Transforms/InstCombine/log-pow-nofastmath.ll b/llvm/test/Transforms/InstCombine/log-pow-nofastmath.ll
index 0811e63..6c37c54 100644
--- a/llvm/test/Transforms/InstCombine/log-pow-nofastmath.ll
+++ b/llvm/test/Transforms/InstCombine/log-pow-nofastmath.ll
@@ -13,5 +13,18 @@
 ; CHECK:   ret double %call
 ; CHECK: }
 
+define double @test3(double %x) #0 {
+  %call2 = call double @exp2(double %x) #0
+  %call3 = call double @log(double %call2) #0
+  ret double %call3
+}
+
+; CHECK-LABEL: @test3
+; CHECK:   %call2 = call double @exp2(double %x)
+; CHECK:   %call3 = call double @log(double %call2)
+; CHECK:   ret double %call3
+; CHECK: }
+
 declare double @log(double) #0
+declare double @exp2(double)
 declare double @llvm.pow.f64(double, double)