ScanInfo holds the information to assist in lowering of Scan reduction. More...

#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"

Public Member Functions
	ScanInfo ()

	~ScanInfo ()

Public Attributes
llvm::BasicBlock *	OMPBeforeScanBlock = nullptr
	Dominates the body of the loop before scan directive.

llvm::BasicBlock *	OMPAfterScanBlock = nullptr
	Dominates the body of the loop before scan directive.

llvm::BasicBlock *	OMPScanDispatch = nullptr
	Controls the flow to before or after scan blocks.

llvm::BasicBlock *	OMPScanLoopExit = nullptr
	Exit block of loop body.

llvm::BasicBlock *	OMPScanInit = nullptr
	Block before loop body where scan initializations are done.

llvm::BasicBlock *	OMPScanFinish = nullptr
	Block after loop body where scan finalizations are done.

bool	OMPFirstScanLoop = false
	If true, it indicates Input phase is lowered; else it indicates ScanPhase is lowered.

llvm::SmallDenseMap< llvm::Value , llvm::Value > *	ScanBuffPtrs
	Maps the private reduction variable to the pointer of the temporary buffer.

llvm::Value *	IV
	Keeps track of value of iteration variable for input/scan loop to be used for Scan directive lowering.

llvm::Value *	Span
	Stores the span of canonical loop being lowered to be used for temporary buffer allocation or Finalization.

Detailed Description

ScanInfo holds the information to assist in lowering of Scan reduction.

Before lowering, the body of the for loop specifying scan reduction is expected to have the following structure

Loop Body Entry
   |
Code before the scan directive
   |
Scan Directive
   |
Code after the scan directive
   |
Loop Body Exit

When createCanonicalScanLoops is executed, the bodyGen callback of it transforms the body to:

Loop Body Entry
   |
OMPScanDispatch

OMPBeforeScanBlock
   |
OMPScanLoopExit
   |
Loop Body Exit

The insert point is updated to the first insert point of OMPBeforeScanBlock. It dominates the control flow of code generated until scan directive is encountered and OMPAfterScanBlock dominates the control flow of code generated after scan is encountered. The successor of OMPScanDispatch can be OMPBeforeScanBlock or OMPAfterScanBlock based on 1.whether it is in Input phase or Scan Phase , 2. whether it is an exclusive or inclusive scan. This jump is added when createScan is executed. If input loop is being generated, if it is inclusive scan, OMPAfterScanBlock succeeds OMPScanDispatch , if exclusive, OMPBeforeScanBlock succeeds OMPDispatch and vice versa for scan loop. At the end of the input loop, temporary buffer is populated and at the beginning of the scan loop, temporary buffer is read. After scan directive is encountered, insertion point is updated to OMPAfterScanBlock as it is expected to dominate the code after the scan directive. Both Before and After scan blocks are succeeded by OMPScanLoopExit. Temporary buffer allocations are done in ScanLoopInit block before the lowering of for-loop. The results are copied back to reduction variable in ScanLoopFinish block.

Definition at line 3959 of file OMPIRBuilder.h.