Commit Graph

3 Commits

Author SHA1 Message Date
Eli Friedman 01d349bab1 Remove -cc1 option "-backend-option".
It means the same thing as -mllvm; there isn't any reason to have two
options which do the same thing.

Differential Revision: https://reviews.llvm.org/D45109

llvm-svn: 329965
2018-04-12 22:21:36 +00:00
Bradley Smith 04ee8aa1fc [AArch64] Enable A53 erratum workaround (835769) by default for Android targets
llvm-svn: 219933
2014-10-16 16:35:14 +00:00
Bradley Smith 9ff64332a0 [AArch64] Add workaround for Cortex-A53 erratum (835769)
Some early revisions of the Cortex-A53 have an erratum (835769) whereby it is
possible for a 64-bit multiply-accumulate instruction in AArch64 state to
generate an incorrect result.  The details are quite complex and hard to
determine statically, since branches in the code may exist in some
circumstances, but all cases end with a memory (load, store, or prefetch)
instruction followed immediately by the multiply-accumulate operation.

The safest work-around for this issue is to make the compiler avoid emitting
multiply-accumulate instructions immediately after memory instructions and the
simplest way to do this is to insert a NOP.

This patch implements clang options to enable this workaround in the backend.

The work-around code generation is not enabled by default.

llvm-svn: 219604
2014-10-13 10:16:06 +00:00