[llvm-branch-commits] [llvm-branch] r115839 - in /llvm/branches/ggreif/switch-opts: lib/Transforms/Scalar/CodeGenPrepare.cpp test/CodeGen/X86/switch-and.ll

[Gabor Greif]

Author: ggreif
Date: Wed Oct  6 16:14:40 2010
New Revision: 115839

URL: http://llvm.org/viewvc/llvm-project?rev=115839&view=rev
Log:
get rid of top value in switch by doing an UGT comparison against the middle value; update testcase

Modified:
    llvm/branches/ggreif/switch-opts/lib/Transforms/Scalar/CodeGenPrepare.cpp
    llvm/branches/ggreif/switch-opts/test/CodeGen/X86/switch-and.ll

Modified: llvm/branches/ggreif/switch-opts/lib/Transforms/Scalar/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/ggreif/switch-opts/lib/Transforms/Scalar/CodeGenPrepare.cpp?rev=115839&r1=115838&r2=115839&view=diff
==============================================================================
--- llvm/branches/ggreif/switch-opts/lib/Transforms/Scalar/CodeGenPrepare.cpp (original)
+++ llvm/branches/ggreif/switch-opts/lib/Transforms/Scalar/CodeGenPrepare.cpp Wed Oct  6 16:14:40 2010
@@ -878,11 +878,14 @@
 static BasicBlock*
 ChopOffSwitchLeg(SwitchInst *I, Value *OrigCondition, ConstantInt *Val,
                  BasicBlock *Old, const char *CmpName, const char *BlockName,
-                 CmpInst::Predicate Crit = CmpInst::ICMP_EQ) {
+                 CmpInst::Predicate Crit = CmpInst::ICMP_EQ,
+								 ConstantInt *Against = 0) {
+  if (!Against) Against = Val;
+
   if (unsigned Leg = I->findCaseValue(Val)) {
     BasicBlock *New = Old->splitBasicBlock(I, BlockName);        
     Old->getTerminator()->eraseFromParent();
-    Instruction *Cmp = new ICmpInst(*Old, Crit, OrigCondition, Val, CmpName);
+    Instruction *Cmp = new ICmpInst(*Old, Crit, OrigCondition, Against, CmpName);
     BranchInst::Create(I->getSuccessor(Leg), New, Cmp, Old);
     I->removeCase(Leg);
     return New;
@@ -929,11 +932,16 @@
         if (unknown > 2) return true;
         unknown += KnownOne.countPopulation();
         if (unknown > 2) return true;
-        APInt Middle(KnownZeroInverted | KnownOne);
+        APInt Top(KnownZeroInverted | KnownOne);
+        APInt Middle(Top);
         Middle.clear(KnownZeroInverted.countTrailingZeros());
         ConstantInt *Mid(cast<ConstantInt>(ConstantInt::get(Ty, Middle)));
 
         if (BasicBlock *New2 = ChopOffSwitchLeg(I, OrigCondition, Mid, New, "mid?", "nz.non-middle")) {
+					ConstantInt *T(cast<ConstantInt>(ConstantInt::get(Ty, Top)));
+					if (BasicBlock *New3 = ChopOffSwitchLeg(I, OrigCondition, T, New2,
+																									"top?", "nz.bottom", CmpInst::ICMP_UGT, Mid)) {
+					}
         }
         return true;
       }

Modified: llvm/branches/ggreif/switch-opts/test/CodeGen/X86/switch-and.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/ggreif/switch-opts/test/CodeGen/X86/switch-and.ll?rev=115839&r1=115838&r2=115839&view=diff
==============================================================================
--- llvm/branches/ggreif/switch-opts/test/CodeGen/X86/switch-and.ll (original)
+++ llvm/branches/ggreif/switch-opts/test/CodeGen/X86/switch-and.ll Wed Oct  6 16:14:40 2010
@@ -16,6 +16,7 @@
  %and = and i64 %0, 3
  %conv = trunc i64 %and to i32
  switch i32 %conv, label %sw.epilog [
+
 ;; CHECK: %tst = icmp eq i32 %conv, 0
 ;; CHECK-NEXT: br i1 %tst, label %sw.bb, label %nz
    i32 0, label %sw.bb
@@ -25,10 +26,13 @@
 ;; CHECK-NEXT: br i1 %"mid?", label %sw.bb8, label %nz.non-middle
 
 ;; CHECK: nz.non-middle:
+;; CHECK-NEXT: %"top?" = icmp ugt i32 %conv, 2
+;; CHECK-NEXT: br i1 %"top?", label %sw.bb6, label %nz.bottom
+
+;; CHECK: nz.bottom:
 ;; CHECK-NEXT: switch i32 %conv, label %sw.epilog
 ;; CHECK-NEXT: i32 1, label %sw.bb
    i32 1, label %sw.bb
-;; CHECK-NEXT: i32 3, label %sw.bb6
    i32 3, label %sw.bb6
    i32 2, label %sw.bb8
 ;; CHECK-NEXT: ]