only run GlobalDCE at -O3 and run it late instead of early.

GlobalOpt already deletes trivially dead functions/globals,
so GlobalDCE only adds values for cycles of dead things.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85731 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-11-01 19:09:12 +00:00
parent ec4c7b9766
commit c92712184f

View File

@ -99,7 +99,7 @@ namespace llvm {
PM->add(createCFGSimplificationPass()); // Clean up disgusting code
if (UnitAtATime) {
PM->add(createGlobalOptimizerPass()); // Optimize out global vars
PM->add(createGlobalDCEPass()); // Remove unused fns and globs
PM->add(createIPSCCPPass()); // IP SCCP
PM->add(createDeadArgEliminationPass()); // Dead argument elimination
}
@ -149,10 +149,15 @@ namespace llvm {
if (UnitAtATime) {
PM->add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
PM->add(createDeadTypeEliminationPass()); // Eliminate dead types
}
if (OptimizationLevel > 1 && UnitAtATime)
PM->add(createConstantMergePass()); // Merge dup global constants
// GlobalOpt already deletes dead functions and globals, at -O3 try a
// late pass of GlobalDCE. It is capable of deleting dead cycles.
if (OptimizationLevel > 2)
PM->add(createGlobalDCEPass()); // Remove dead fns and globals.
if (OptimizationLevel > 1)
PM->add(createConstantMergePass()); // Merge dup global constants
}
}
static inline void addOnePass(PassManager *PM, Pass *P, bool AndVerify) {