[PATCH] D123625: [SimplifyCFG] make a debug option for case max when converting switch to select

[Sanjay Patel via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGcd0d0d633bc6: [SimplifyCFG] make a debug option for case max when converting switch to select (authored by spatel).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D123625/new/

https://reviews.llvm.org/D123625

Files:
  llvm/lib/Transforms/Utils/SimplifyCFG.cpp


Index: llvm/lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -168,6 +168,10 @@
     "simplifycfg-merge-compatible-invokes", cl::Hidden, cl::init(true),
     cl::desc("Allow SimplifyCFG to merge invokes together when appropriate"));
 
+static cl::opt<unsigned> MaxSwitchCasesPerResult(
+    "max-switch-cases-per-result", cl::Hidden, cl::init(2),
+    cl::desc("Limit cases to analyze when converting a switch to select"));
+
 STATISTIC(NumBitMaps, "Number of switch instructions turned into bitmaps");
 STATISTIC(NumLinearMaps,
           "Number of switch instructions turned into linear mapping");
@@ -5602,9 +5606,9 @@
 
 // Helper function used to add CaseVal to the list of cases that generate
 // Result. Returns the updated number of cases that generate this result.
-static uintptr_t mapCaseToResult(ConstantInt *CaseVal,
-                                 SwitchCaseResultVectorTy &UniqueResults,
-                                 Constant *Result) {
+static size_t mapCaseToResult(ConstantInt *CaseVal,
+                              SwitchCaseResultVectorTy &UniqueResults,
+                              Constant *Result) {
   for (auto &I : UniqueResults) {
     if (I.first == Result) {
       I.second.push_back(CaseVal);
@@ -5620,12 +5624,13 @@
 // results for the PHI node of the common destination block for a switch
 // instruction. Returns false if multiple PHI nodes have been found or if
 // there is not a common destination block for the switch.
-static bool
-initializeUniqueCases(SwitchInst *SI, PHINode *&PHI, BasicBlock *&CommonDest,
-                      SwitchCaseResultVectorTy &UniqueResults,
-                      Constant *&DefaultResult, const DataLayout &DL,
-                      const TargetTransformInfo &TTI,
-                      uintptr_t MaxUniqueResults, uintptr_t MaxCasesPerResult) {
+static bool initializeUniqueCases(SwitchInst *SI, PHINode *&PHI,
+                                  BasicBlock *&CommonDest,
+                                  SwitchCaseResultVectorTy &UniqueResults,
+                                  Constant *&DefaultResult,
+                                  const DataLayout &DL,
+                                  const TargetTransformInfo &TTI,
+                                  uintptr_t MaxUniqueResults) {
   for (auto &I : SI->cases()) {
     ConstantInt *CaseVal = I.getCaseValue();
 
@@ -5640,11 +5645,11 @@
       return false;
 
     // Add the case->result mapping to UniqueResults.
-    const uintptr_t NumCasesForResult =
+    const size_t NumCasesForResult =
         mapCaseToResult(CaseVal, UniqueResults, Results.begin()->second);
 
     // Early out if there are too many cases for this result.
-    if (NumCasesForResult > MaxCasesPerResult)
+    if (NumCasesForResult > MaxSwitchCasesPerResult)
       return false;
 
     // Early out if there are too many unique results.
@@ -5772,8 +5777,7 @@
   SwitchCaseResultVectorTy UniqueResults;
   // Collect all the cases that will deliver the same value from the switch.
   if (!initializeUniqueCases(SI, PHI, CommonDest, UniqueResults, DefaultResult,
-                             DL, TTI, /*MaxUniqueResults*/ 2,
-                             /*MaxCasesPerResult*/ 2))
+                             DL, TTI, /*MaxUniqueResults*/ 2))
     return false;
 
   assert(PHI != nullptr && "PHI for value select not found");


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D123625.422468.patch
Type: text/x-patch
Size: 3510 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220413/9e0d9514/attachment.bin>