movw. That is we promote the destination operand to r16. So
%CH = TRUNC_R16_R8 %BP
is emitted as
movw %bp, %cx.
This is incorrect. If %cl is live, it would be clobbered.
Ideally we want to do the opposite, that is emitted it as
movb ??, %ch
But this is not possible since %bp does not have a r8 sub-register.
We are now defining a new register class R16_ which is a subclass of R16
containing only those 16-bit registers that have r8 sub-registers (i.e.
AX - DX). We isel the truncate to two instructions, a MOV16to16_ to copy the
value to the R16_ class, followed by a TRUNC_R16_R8.
Due to bug 770, the register colaescer is not going to coalesce between R16 and
R16_. That will be fixed later so we can eliminate the MOV16to16_. Right now, it
can only be eliminated if we are lucky that source and destination registers are
the same.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28164 91177308-0d34-0410-b5e6-96231b3b80d8
that gets emitted as movl (for r32 to i16, i8) or a movw (for r16 to i8). And
if the destination gets allocated a subregister of the source operand, then
the instruction will not be emitted at all.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28119 91177308-0d34-0410-b5e6-96231b3b80d8
* Cleaned up and tweaked LEA cost analysis code. Removed some hacks.
* Handle ADD $X, c to MOV32ri $X+c. These patterns cannot be autogen'd and
they need to be matched before LEA.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26376 91177308-0d34-0410-b5e6-96231b3b80d8
and ExternalSymbol.
- Use C++ code (rather than tblgen'd selection code) to match the above
mentioned leaf nodes. Do not mutate and nodes and do not record the
selection in CodeGenMap. These nodes should be safe to duplicate. This is
a performance win.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26335 91177308-0d34-0410-b5e6-96231b3b80d8
1. Various asm printer bug.
2. Lowering bug. Now TargetGlobalAddress is wrapped in X86ISD::TGAWrapper.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26324 91177308-0d34-0410-b5e6-96231b3b80d8
Suppose base == %eax and it has multiple uses, then instead of
movl %eax, %ecx
addl $8, %ecx
use
leal 8(%eax), %ecx.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26323 91177308-0d34-0410-b5e6-96231b3b80d8
X86 addressing mode. Currently we do not allow any node whose target node
produces a chain as well as any node that is at the root of the addressing
mode expression tree.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26117 91177308-0d34-0410-b5e6-96231b3b80d8
* Allow a register node as SelectAddr() base.
* ExternalSymbol -> TargetExternalSymbol as direct function callee.
* Use X86::ESP register rather than CopyFromReg(X86::ESP) as stack ptr for
call parmater passing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25207 91177308-0d34-0410-b5e6-96231b3b80d8
for Darwin.
* Added lowering hook for ISD::RET. It inserts CopyToRegs for the return
value (or store / fld / copy to ST(0) for floating point value). This
eliminate the need to write C++ code to handle RET with variable number
of operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24888 91177308-0d34-0410-b5e6-96231b3b80d8
