[llvm] r335198 - Revert "[SCEV] Improve zext(A /u B) and zext(A % B)"

[Tim Shen via llvm-commits]

Author: timshen
Date: Wed Jun 20 19:15:32 2018
New Revision: 335198

URL: http://llvm.org/viewvc/llvm-project?rev=335198&view=rev
Log:
Revert "[SCEV] Improve zext(A /u B) and zext(A % B)"

This reverts commit r335197, as some bots are not happy.

Removed:
    llvm/trunk/test/Analysis/ScalarEvolution/zext-divrem.ll
Modified:
    llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=335198&r1=335197&r2=335198&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Wed Jun 20 19:15:32 2018
@@ -1845,10 +1845,6 @@ private:
   /// accordingly.
   void addToLoopUseLists(const SCEV *S);
 
-  /// Try to match the pattern generated by getURemExpr(A, B). If successful,
-  /// Assign A and B to LHS and RHS, respectively.
-  bool matchURem(const SCEV *Expr, const SCEV *&LHS, const SCEV *&RHS);
-
   FoldingSet<SCEV> UniqueSCEVs;
   FoldingSet<SCEVPredicate> UniquePreds;
   BumpPtrAllocator SCEVAllocator;

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=335198&r1=335197&r2=335198&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Wed Jun 20 19:15:32 2018
@@ -1756,20 +1756,6 @@ ScalarEvolution::getZeroExtendExpr(const
       }
     }
 
-  // zext(A % B) --> zext(A) % zext(B)
-  {
-    const SCEV *LHS;
-    const SCEV *RHS;
-    if (matchURem(Op, LHS, RHS))
-      return getURemExpr(getZeroExtendExpr(LHS, Ty, Depth + 1),
-                         getZeroExtendExpr(RHS, Ty, Depth + 1));
-  }
-
-  // zext(A / B) --> zext(A) / zext(B).
-  if (auto *Div = dyn_cast<SCEVUDivExpr>(Op))
-    return getUDivExpr(getZeroExtendExpr(Div->getLHS(), Ty, Depth + 1),
-                       getZeroExtendExpr(Div->getRHS(), Ty, Depth + 1));
-
   if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) {
     // zext((A + B + ...)<nuw>) --> (zext(A) + zext(B) + ...)<nuw>
     if (SA->hasNoUnsignedWrap()) {
@@ -12167,43 +12153,3 @@ void PredicatedScalarEvolution::print(ra
       OS.indent(Depth + 2) << "--> " << *II->second.second << "\n";
     }
 }
-
-// Match the mathematical pattern A - (A / B) * B, where A and B can be
-// arbitrary expressions.
-// It's not always easy, as A and B can be folded (imagine A is X / 2, and B is
-// 4, A / B becomes X / 8).
-bool ScalarEvolution::matchURem(const SCEV *Expr, const SCEV *&LHS,
-                                const SCEV *&RHS) {
-  const auto *Add = dyn_cast<SCEVAddExpr>(Expr);
-  if (Add == nullptr || Add->getNumOperands() != 2)
-    return false;
-
-  const SCEV *A = Add->getOperand(1);
-  const auto *Mul = dyn_cast<SCEVMulExpr>(Add->getOperand(0));
-
-  if (Mul == nullptr)
-    return false;
-
-  const auto MatchURemWithDivisor = [&](const SCEV *B) {
-    // (SomeExpr + (-(SomeExpr / B) * B)).
-    if (Expr == getURemExpr(A, B)) {
-      LHS = A;
-      RHS = B;
-      return true;
-    }
-    return false;
-  };
-
-  // (SomeExpr + (-1 * (SomeExpr / B) * B)).
-  if (Mul->getNumOperands() == 3 && isa<SCEVConstant>(Mul->getOperand(0)))
-    return MatchURemWithDivisor(Mul->getOperand(1)) ||
-           MatchURemWithDivisor(Mul->getOperand(2));
-
-  // (SomeExpr + ((-SomeExpr / B) * B)) or (SomeExpr + ((SomeExpr / B) * -B)).
-  if (Mul->getNumOperands() == 2)
-    return MatchURemWithDivisor(Mul->getOperand(1)) ||
-           MatchURemWithDivisor(Mul->getOperand(0)) ||
-           MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(1))) ||
-           MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(0)));
-  return false;
-};

Removed: llvm/trunk/test/Analysis/ScalarEvolution/zext-divrem.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/zext-divrem.ll?rev=335197&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/zext-divrem.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/zext-divrem.ll (removed)
@@ -1,42 +0,0 @@
-; RUN: opt -analyze -scalar-evolution -S < %s | FileCheck %s
-
-define i64 @test1(i32 %a, i32 %b) {
-; CHECK-LABEL: @test1
-  %div = udiv i32 %a, %b
-  %zext = zext i32 %div to i64
-; CHECK: %zext
-; CHECK-NEXT: -->  ((zext i32 %a to i64) /u (zext i32 %b to i64))
-  ret i64 %zext
-}
-
-define i64 @test2(i32 %a, i32 %b) {
-; CHECK-LABEL: @test2
-  %rem = urem i32 %a, %b
-  %zext = zext i32 %rem to i64
-; CHECK: %zext
-; CHECK-NEXT: -->  ((zext i32 %a to i64) + (-1 * (zext i32 %b to i64) * ((zext i32 %a to i64) /u (zext i32 %b to i64))))
-  ret i64 %zext
-}
-
-define i64 @test3(i32 %a, i32 %b) {
-; CHECK-LABEL: @test3
-  %div = udiv i32 %a, %b
-  %mul = mul i32 %div, %b
-  %sub = sub i32 %a, %mul
-  %zext = zext i32 %sub to i64
-; CHECK: %zext
-; CHECK-NEXT: -->  ((zext i32 %a to i64) + (-1 * (zext i32 %b to i64) * ((zext i32 %a to i64) /u (zext i32 %b to i64))))
-  ret i64 %zext
-}
-
-define i64 @test4(i32 %t) {
-; CHECK-LABEL: @test4
-  %a = udiv i32 %t, 2
-  %div = udiv i32 %t, 112
-  %mul = mul i32 %div, 56
-  %sub = sub i32 %a, %mul
-  %zext = zext i32 %sub to i64
-; CHECK: %zext
-; CHECK-NEXT: -->  ((-56 * ((zext i32 %t to i64) /u 112)) + ((zext i32 %t to i64) /u 2))
-  ret i64 %zext
-}