Eliminate redundant CR moves on PPC32.
The 32-bit ABI requires CR bit 6 to be set if the call has fp arguments and
unset if it doesn't. The solution up to now was to insert a MachineNode to
set/unset the CR bit, which produces a CR vreg. This vreg was then copied
into CR bit 6. When the register allocator saw a bunch of these in the same
function, it allocated the set/unset CR bit in some random CR register (1
extra instruction) and then emitted CR moves before every vararg function
call, rather than just setting and unsetting CR bit 6 directly before every
vararg function call. This patch instead inserts a PPCcrset/PPCcrunset
instruction which are then matched by a dedicated instruction pattern.
Patch by Tobias von Koch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162725 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index b0a013b..902b188 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -174,6 +174,10 @@
/// operand #3 optional in flag
TC_RETURN,
+ /// ch, gl = CR6[UN]SET ch, inglue - Toggle CR bit 6 for SVR4 vararg calls
+ CR6SET,
+ CR6UNSET,
+
/// STD_32 - This is the STD instruction for use with "32-bit" registers.
STD_32 = ISD::FIRST_TARGET_MEMORY_OPCODE,