It improves Win64's prologue/epilogue but it would not affect ia32 and amd64 (lack of nonvolatile XMMs).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126568 91177308-0d34-0410-b5e6-96231b3b80d8
opportunities. For example, this lets it emit this:
movq (%rax), %rcx
addq %rdx, %rcx
instead of this:
movq %rdx, %rcx
addq (%rax), %rcx
in the case where %rdx has subsequent uses. It's the same number
of instructions, and usually the same encoding size on x86, but
it appears faster, and in general, it may allow better scheduling
for the load.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106493 91177308-0d34-0410-b5e6-96231b3b80d8
by the recent FixedStackPseudoSourceValue-related changes, now that
the specific bug that affected it is fixed, in r88954.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88997 91177308-0d34-0410-b5e6-96231b3b80d8
Instead of awkwardly encoding calling-convention information with ISD::CALL,
ISD::FORMAL_ARGUMENTS, ISD::RET, and ISD::ARG_FLAGS nodes, TargetLowering
provides three virtual functions for targets to override:
LowerFormalArguments, LowerCall, and LowerRet, which replace the custom
lowering done on the special nodes. They provide the same information, but
in a more immediately usable format.
This also reworks much of the target-independent tail call logic. The
decision of whether or not to perform a tail call is now cleanly split
between target-independent portions, and the target dependent portion
in IsEligibleForTailCallOptimization.
This also synchronizes all in-tree targets, to help enable future
refactoring and feature work.
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out of sync with regular cc.
The only difference between the tail call cc and the normal
cc was that one parameter register - R9 - was reserved for
calling functions through a function pointer. After time the
tail call cc has gotten out of sync with the regular cc.
We can use R11 which is also caller saved but not used as
parameter register for potential function pointers and
remove the special tail call cc on x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73233 91177308-0d34-0410-b5e6-96231b3b80d8
