llvm-6502/lib/Target/ARM/README-Thumb2.txt
Evan Cheng 861986401e It turns out most of the thumb2 instructions are not allowed to touch SP. The semantics of such instructions are unpredictable. We have just been lucky that tests have been passing.
This patch takes pain to ensure all the PEI lowering code does the right thing when lowering frame indices, insert code to manipulate stack pointers, etc. It's also custom lowering dynamic stack alloc into pseudo instructions so we can insert the right instructions at scheduling time.

This fixes PR4659 and PR4682.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78361 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-07 00:34:42 +00:00

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//===---------------------------------------------------------------------===//
// Random ideas for the ARM backend (Thumb2 specific).
//===---------------------------------------------------------------------===//
We should be using ADD / SUB rd, sp, rm <shift> instructions.
copyRegToReg should use tMOVgpr2gpr instead of t2MOVr?