RegAlloc superpass: includes phi elimination, coalescing, and scheduling.
Creates a configurable regalloc pipeline.
Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa.
When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>.
CodeGen transformation passes are never "required" as an analysis
ProcessImplicitDefs does not require LiveVariables.
We have a plan to massively simplify some of the early passes within the regalloc superpass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150226 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index ae63e76..7d98935 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -33,6 +33,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/ErrorHandling.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
@@ -41,6 +42,7 @@
using namespace llvm;
char LiveVariables::ID = 0;
+char &llvm::LiveVariablesID = LiveVariables::ID;
INITIALIZE_PASS_BEGIN(LiveVariables, "livevars",
"Live Variable Analysis", false, false)
INITIALIZE_PASS_DEPENDENCY(UnreachableMachineBlockElim)
@@ -511,6 +513,12 @@
std::fill(PhysRegUse, PhysRegUse + NumRegs, (MachineInstr*)0);
PHIJoins.clear();
+ // FIXME: LiveIntervals will be updated to remove its dependence on
+ // LiveVariables to improve compilation time and eliminate bizarre pass
+ // dependencies. Until then, we can't change much in -O0.
+ if (!MRI->isSSA())
+ report_fatal_error("regalloc=... not currently supported with -O0");
+
analyzePHINodes(mf);
// Calculate live variable information in depth first order on the CFG of the