[DA] Add option to run only SIV routines (#157084)

This patch introduces a new option, `da-run-siv-routines-only`, which
runs only the SIV family routines in the DA. This is useful for testing
(regression tests, not dependence tests) as it helps detect behavioral
changes in the SIV routines. Actually, regarding the test cases added in
#157085, fixing the incorrect result requires changes across multiple
functions (at a minimum, `exactSIVtest`, `gcdMIVtest` and
`symbolicRDIVtest`). It is difficult to address all of them at once.

This patch also generates the CHECK directives using the new option for
`ExactSIV.ll` as it is necessary for subsequent patches. However, I
believe it will also be useful for other `xxSIV.ll` tests. Notably, the
SIV family routines tend to be affected by other routines, as they are
typically invoked at the beginning of the overall analysis.

Author: kasuga-fj

llvm/lib/Analysis/DependenceAnalysis.cpp

@@ -121,6 +121,12 @@ static cl::opt<unsigned> MIVMaxLevelThreshold(
     cl::desc("Maximum depth allowed for the recursive algorithm used to "
              "explore MIV direction vectors."));
 
+static cl::opt<bool> RunSIVRoutinesOnly(
+    "da-run-siv-routines-only", cl::init(false), cl::ReallyHidden,
+    cl::desc("Run only SIV routines and disable others (ZIV, RDIV, and MIV). "
+             "The purpose is mainly to exclude the influence of those routines "
+             "in regression tests for SIV routines."));
+
 //===----------------------------------------------------------------------===//
 // basics
 
@@ -1980,6 +1986,8 @@ bool DependenceInfo::exactRDIVtest(const SCEV *SrcCoeff, const SCEV *DstCoeff,
                                    const SCEV *SrcConst, const SCEV *DstConst,
                                    const Loop *SrcLoop, const Loop *DstLoop,
                                    FullDependence &Result) const {
+  if (RunSIVRoutinesOnly)
+    return false;
   LLVM_DEBUG(dbgs() << "\tExact RDIV test\n");
   LLVM_DEBUG(dbgs() << "\t    SrcCoeff = " << *SrcCoeff << " = AM\n");
   LLVM_DEBUG(dbgs() << "\t    DstCoeff = " << *DstCoeff << " = BM\n");
@@ -2124,6 +2132,8 @@ bool DependenceInfo::symbolicRDIVtest(const SCEV *A1, const SCEV *A2,
                                       const SCEV *C1, const SCEV *C2,
                                       const Loop *Loop1,
                                       const Loop *Loop2) const {
+  if (RunSIVRoutinesOnly)
+    return false;
   ++SymbolicRDIVapplications;
   LLVM_DEBUG(dbgs() << "\ttry symbolic RDIV test\n");
   LLVM_DEBUG(dbgs() << "\t    A1 = " << *A1);
@@ -2433,6 +2443,8 @@ bool DependenceInfo::accumulateCoefficientsGCD(const SCEV *Expr,
 // to "a common divisor".
 bool DependenceInfo::gcdMIVtest(const SCEV *Src, const SCEV *Dst,
                                 FullDependence &Result) const {
+  if (RunSIVRoutinesOnly)
+    return false;
   LLVM_DEBUG(dbgs() << "starting gcd\n");
   ++GCDapplications;
   unsigned BitWidth = SE->getTypeSizeInBits(Src->getType());
@@ -2599,6 +2611,8 @@ bool DependenceInfo::gcdMIVtest(const SCEV *Src, const SCEV *Dst,
 bool DependenceInfo::banerjeeMIVtest(const SCEV *Src, const SCEV *Dst,
                                      const SmallBitVector &Loops,
                                      FullDependence &Result) const {
+  if (RunSIVRoutinesOnly)
+    return false;
   LLVM_DEBUG(dbgs() << "starting Banerjee\n");
   ++BanerjeeApplications;
   LLVM_DEBUG(dbgs() << "    Src = " << *Src << '\n');