diff --git a/lib/Transforms/IPO/FunctionAttrs.cpp b/lib/Transforms/IPO/FunctionAttrs.cpp
index 65faef3..e831524 100644
--- a/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -152,6 +152,11 @@
       if (I->mayWriteToMemory())
         // Writes memory.  Just give up.
         return false;
+
+      if (isa<MallocInst>(I))
+        // MallocInst claims not to write memory!  PR3754.
+        return false;
+
       // If this instruction may read memory, remember that.
       ReadsMemory |= I->mayReadFromMemory();
     }
diff --git a/test/Transforms/FunctionAttrs/2009-05-06-Malloc.ll b/test/Transforms/FunctionAttrs/2009-05-06-Malloc.ll
new file mode 100644
index 0000000..4022033
--- /dev/null
+++ b/test/Transforms/FunctionAttrs/2009-05-06-Malloc.ll
@@ -0,0 +1,7 @@
+; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | not grep read
+; PR3754
+
+define i8* @m(i32 %size) {
+	%tmp = malloc i8, i32 %size		; <i8*> [#uses=1]
+	ret i8* %tmp
+}