Be less aggressive about hinting in RAFast.

In particular, don't spill dirty registers only to satisfy a hint. It is
not worth it.

The attached test case provides an example where the fast allocator
would spill a register when other registers are available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132900 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/fast-isel-gep.ll b/test/CodeGen/X86/fast-isel-gep.ll
index 48abfd0..1a2e34e 100644
--- a/test/CodeGen/X86/fast-isel-gep.ll
+++ b/test/CodeGen/X86/fast-isel-gep.ll
@@ -24,7 +24,7 @@
        %t15 = load i32* %t9            ; <i32> [#uses=1]
        ret i32 %t15
 ; X32: test2:
-; X32:  	movl	(%edx,%ecx,4), %eax
+; X32:  	movl	(%edx,%ecx,4), %e
 ; X32:  	ret
 
 ; X64: test2: