[llvm-mca] Correctly set the ReadAdvance information for register use operands.

The tool was passing the wrong operand index to method
MCSubtargetInfo::getReadAdvanceCycles(). That method requires a "UseIdx", and
not the operand index. This was found when testing X86 code where instructions
had a memory folded operand.

This patch fixes the issue and adds test read-advance-1.s to ensure that
the ReadAfterLd (a ReadAdvance of 3cy) information is correctly used.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328790 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed