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- Rev 3735 2011-09-10 02:42:57 GMT
- Author: yug
- Log message:
- A new implementation for the open64's support for DSP Zero-Delay-Loop(ZDL) feature. This ZDL contribution is a co-operational approach of global scalar optimizer WOPT and the Code Generation component CG. The common ZDL features, i.e, the loop counting mechanism hidden and bottom loop condition abstracted are implemented in WOPT with minimized changes while keeping the maximum optimizing result. A pseudo branch op method is introduced to expand ZDL WHIRL operator and delay the ZDL hardware instruction generation to the very last phase of CG loop optimization. This lazy implementation helps keeping the compatibility with other CG loop optimizations to produce the most optimal code. With the new ZDL implementation, open64 provides the equal expressibility to gcc's doloop_begin, doloop_end and decrement_and_branch_until_zero patterns.
#pragma zdl off
INT CG_LOOP_ZDL_Gen(LOOP_DESCR*); //cg_loop.cxx
void Emit_Phase_Validity_Check(void); //cgemit.cxx
void Target_Specific_ZDLBR_Expansion(TN* target_tn); //whirl2ops.cxx
Code Review: Fred Chow, Lai Jianxin and Sun Chan.