Introduce a pass to insert vzeroupper instructions to avoid AVX to
SSE transition penalty. The pass is enabled through the "x86-use-vzeroupper"
llc command line option. This is only the first step (very naive and
conservative one) to sketch out the idea, but proper DFA is coming next
to allow smarter decisions. Comments and ideas now and in further commits
will be very appreciated.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138317 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86.h b/lib/Target/X86/X86.h
index d1e1933..d480d0c 100644
--- a/lib/Target/X86/X86.h
+++ b/lib/Target/X86/X86.h
@@ -48,6 +48,11 @@
/// crossings.
FunctionPass *createSSEDomainFixPass();
+/// createX86IssueVZeroUpperPass - This pass inserts AVX vzeroupper instructions
+/// before each call to avoid transition penalty between functions encoded with
+/// AVX and SSE.
+FunctionPass *createX86IssueVZeroUpperPass();
+
/// createX86CodeEmitterPass - Return a pass that emits the collected X86 code
/// to the specified MCE object.
FunctionPass *createX86JITCodeEmitterPass(X86TargetMachine &TM,