From e880efe446f731b73558542c12a6f980b8baa765 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 7 Nov 2009 07:50:34 +0000
Subject: [PATCH] Fix PR5421 by APInt'izing switch lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86354 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../SelectionDAG/SelectionDAGBuild.cpp        | 30 ++++++++++---------
 lib/CodeGen/SelectionDAG/SelectionDAGBuild.h  |  6 ++--
 test/CodeGen/Generic/switch-lower.ll          | 20 +++++++++++--
 3 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index 1ff1cd30f24..53822042a21 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -1743,19 +1743,19 @@ bool SelectionDAGLowering::handleJTSwitchCase(CaseRec& CR,
   Case& FrontCase = *CR.Range.first;
   Case& BackCase  = *(CR.Range.second-1);
 
-  const APInt& First = cast<ConstantInt>(FrontCase.Low)->getValue();
-  const APInt& Last  = cast<ConstantInt>(BackCase.High)->getValue();
+  const APInt &First = cast<ConstantInt>(FrontCase.Low)->getValue();
+  const APInt &Last  = cast<ConstantInt>(BackCase.High)->getValue();
 
-  size_t TSize = 0;
+  APInt TSize(First.getBitWidth(), 0);
   for (CaseItr I = CR.Range.first, E = CR.Range.second;
        I!=E; ++I)
     TSize += I->size();
 
-  if (!areJTsAllowed(TLI) || TSize <= 3)
+  if (!areJTsAllowed(TLI) || TSize.ult(APInt(First.getBitWidth(), 4)))
     return false;
 
   APInt Range = ComputeRange(First, Last);
-  double Density = (double)TSize / Range.roundToDouble();
+  double Density = TSize.roundToDouble() / Range.roundToDouble();
   if (Density < 0.4)
     return false;
 
@@ -1849,32 +1849,34 @@ bool SelectionDAGLowering::handleBTSplitSwitchCase(CaseRec& CR,
   // Size is the number of Cases represented by this range.
   unsigned Size = CR.Range.second - CR.Range.first;
 
-  const APInt& First = cast<ConstantInt>(FrontCase.Low)->getValue();
-  const APInt& Last  = cast<ConstantInt>(BackCase.High)->getValue();
+  const APInt &First = cast<ConstantInt>(FrontCase.Low)->getValue();
+  const APInt &Last  = cast<ConstantInt>(BackCase.High)->getValue();
   double FMetric = 0;
   CaseItr Pivot = CR.Range.first + Size/2;
 
   // Select optimal pivot, maximizing sum density of LHS and RHS. This will
   // (heuristically) allow us to emit JumpTable's later.
-  size_t TSize = 0;
+  APInt TSize(First.getBitWidth(), 0);
   for (CaseItr I = CR.Range.first, E = CR.Range.second;
        I!=E; ++I)
     TSize += I->size();
 
-  size_t LSize = FrontCase.size();
-  size_t RSize = TSize-LSize;
+  APInt LSize = FrontCase.size();
+  APInt RSize = TSize-LSize;
   DEBUG(errs() << "Selecting best pivot: \n"
                << "First: " << First << ", Last: " << Last <<'\n'
                << "LSize: " << LSize << ", RSize: " << RSize << '\n');
   for (CaseItr I = CR.Range.first, J=I+1, E = CR.Range.second;
        J!=E; ++I, ++J) {
-    const APInt& LEnd = cast<ConstantInt>(I->High)->getValue();
-    const APInt& RBegin = cast<ConstantInt>(J->Low)->getValue();
+    const APInt &LEnd = cast<ConstantInt>(I->High)->getValue();
+    const APInt &RBegin = cast<ConstantInt>(J->Low)->getValue();
     APInt Range = ComputeRange(LEnd, RBegin);
     assert((Range - 2ULL).isNonNegative() &&
            "Invalid case distance");
-    double LDensity = (double)LSize / (LEnd - First + 1ULL).roundToDouble();
-    double RDensity = (double)RSize / (Last - RBegin + 1ULL).roundToDouble();
+    double LDensity = (double)LSize.roundToDouble() / 
+                           (LEnd - First + 1ULL).roundToDouble();
+    double RDensity = (double)RSize.roundToDouble() /
+                           (Last - RBegin + 1ULL).roundToDouble();
     double Metric = Range.logBase2()*(LDensity+RDensity);
     // Should always split in some non-trivial place
     DEBUG(errs() <<"=>Step\n"
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
index a0ec7aabd8a..bde2f3b232f 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
@@ -193,9 +193,9 @@ class SelectionDAGLowering {
     Case() : Low(0), High(0), BB(0) { }
     Case(Constant* low, Constant* high, MachineBasicBlock* bb) :
       Low(low), High(high), BB(bb) { }
-    uint64_t size() const {
-      uint64_t rHigh = cast<ConstantInt>(High)->getSExtValue();
-      uint64_t rLow  = cast<ConstantInt>(Low)->getSExtValue();
+    APInt size() const {
+      const APInt &rHigh = cast<ConstantInt>(High)->getValue();
+      const APInt &rLow  = cast<ConstantInt>(Low)->getValue();
       return (rHigh - rLow + 1ULL);
     }
   };
diff --git a/test/CodeGen/Generic/switch-lower.ll b/test/CodeGen/Generic/switch-lower.ll
index eb240edc7c6..1cefe82ce3d 100644
--- a/test/CodeGen/Generic/switch-lower.ll
+++ b/test/CodeGen/Generic/switch-lower.ll
@@ -1,8 +1,22 @@
 ; RUN: llc < %s
+
+
+; PR5421
+define void @test1() {
+entry:
+  switch i128 undef, label %exit [
+    i128 55340232221128654848, label %exit
+    i128 92233720368547758080, label %exit
+    i128 73786976294838206464, label %exit
+    i128 147573952589676412928, label %exit
+  ]
+exit:
+  unreachable
+}
+
+
 ; PR1197
-
-
-define void @exp_attr__expand_n_attribute_reference() {
+define void @test2() {
 entry:
 	br i1 false, label %cond_next954, label %cond_true924