On 12/01/2016 04:21 AM, Paolo Bonzini wrote:
In code like the following from KVM:/* it is a read fault? */ error_code = (exit_qualification << 2) & PFERR_FETCH_MASK; it would be nicer to write /* it is a read fault? */ error_code = (exit_qualification & VMX_EPT_READ_FAULT_MASK) ? PFERR_FETCH_MASK : 0; instead of having to know the difference between the positions of the source and destination bits. LLVM catches the latter just fine (which is why I am sending this in stage 3...), but GCC does not, so this patch adds two patterns to catch it. The combine.c hunk of v1 has been committed already. Bootstrapped/regtested x86_64-pc-linux-gnu, ok? Paolo 2016-11-26 Paolo Bonzini <bonz...@gnu.org> * match.pd: Simplify X ? C : 0 where C is a power of 2 and X tests a single bit. 2016-11-26 Paolo Bonzini <bonz...@gnu.org> * gcc.dg/fold-and-lshift.c, gcc.dg/fold-and-rshift-1.c, gcc.dg/fold-and-rshift-2.c: New testcases.
OK. jeff
