[PATCH] D37250: [X86] Apply SlowIncDec feature to Sandybridge/Ivybridge CPUs as well

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

I think Pentium 4 and Silvermont read the old CF value and pass it through the INC/DEC instruction.

I think the "core" line prior to Sandy Bridge any instruction that reads the CF flag after INC/DEC experienced a stall until the INC/DEC instruction retired.

I think from Sandy Bridge onward, it is no longer a stall until retirement, but an instruction that reads the CF flag after INC/DEC become dependent on the last writer of CF before the INC/DEC.


https://reviews.llvm.org/D37250