Revert "[ScalarEvolution] createSCEV(): recognize `udiv`/`urem` disguised as an `sdiv`/`srem`"

[goncharov]

Summary

This reverts commit 2c16100e6f72075564ea1f67fa5a82c269dafcd3.

ninja check-polly fails:

Polly :: Isl/CodeGen/MemAccess/generate-all.ll
Polly :: ScopInfo/multidim_srem.ll

llvm/lib/Analysis/ScalarEvolution.cpp

case Instruction::SExt:
     return getSignExtendExpr(getSCEV(U->getOperand(0)), U->getType());
 
   case Instruction::BitCast:
     // BitCasts are no-op casts so we just eliminate the cast.
     if (isSCEVable(U->getType()) && isSCEVable(U->getOperand(0)->getType()))
       return getSCEV(U->getOperand(0));
     break;
 
-  case Instruction::SDiv:
-    // If both operands are non-negative, this is just an udiv.
-    if (isKnownNonNegative(getSCEV(U->getOperand(0))) &&
-        isKnownNonNegative(getSCEV(U->getOperand(1))))
-      return getUDivExpr(getSCEV(U->getOperand(0)), getSCEV(U->getOperand(1)));
-    break;
-
-  case Instruction::SRem:
-    // If both operands are non-negative, this is just an urem.
-    if (isKnownNonNegative(getSCEV(U->getOperand(0))) &&
-        isKnownNonNegative(getSCEV(U->getOperand(1))))
-      return getURemExpr(getSCEV(U->getOperand(0)), getSCEV(U->getOperand(1)));
-    break;
-
   // It's tempting to handle inttoptr and ptrtoint as no-ops, however this can
   // lead to pointer expressions which cannot safely be expanded to GEPs,
   // because ScalarEvolution doesn't respect the GEP aliasing rules when
   // simplifying integer expressions.
 
   case Instruction::GetElementPtr:
     return createNodeForGEP(cast<GEPOperator>(U));
 

llvm/test/Analysis/ScalarEvolution/sdiv.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
 ; RUN: opt < %s -scalar-evolution -analyze | FileCheck %s
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 define dso_local void @_Z4loopi(i32 %width) local_unnamed_addr #0 {
 ; CHECK-LABEL: '_Z4loopi'
 ; CHECK-NEXT:  Classifying expressions for: @_Z4loopi
 ; CHECK-NEXT:    %storage = alloca [2 x i32], align 4
 ; CHECK-NEXT:    --> %storage U: [0,-3) S: [-9223372036854775808,9223372036854775805)
 ; CHECK-NEXT:    %0 = bitcast [2 x i32]* %storage to i8*
 ; CHECK-NEXT:    --> %storage U: [0,-3) S: [-9223372036854775808,9223372036854775805)
 ; CHECK-NEXT:    %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
 ; CHECK-NEXT:    --> {0,+,1}<nuw><nsw><%for.cond> U: [0,-2147483648) S: [0,-2147483648) Exits: %width LoopDispositions: { %for.cond: Computable }
 ; CHECK-NEXT:    %rem = sdiv i32 %i.0, 2
-; CHECK-NEXT:    --> ({0,+,1}<nuw><nsw><%for.cond> /u 2) U: [0,1073741824) S: [0,1073741824) Exits: (%width /u 2) LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT:    --> %rem U: full-set S: [-1073741824,1073741824) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %idxprom = sext i32 %rem to i64
-; CHECK-NEXT:    --> ({0,+,1}<nuw><nsw><%for.cond> /u 2) U: [0,2147483648) S: [0,2147483648) Exits: ((zext i32 %width to i64) /u 2) LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT:    --> (sext i32 %rem to i64) U: [-2147483648,2147483648) S: [-1073741824,1073741824) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* %storage, i64 0, i64 %idxprom
-; CHECK-NEXT:    --> ((4 * ({0,+,1}<nuw><nsw><%for.cond> /u 2))<nuw><nsw> + %storage)<nsw> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: ((4 * ((zext i32 %width to i64) /u 2))<nuw><nsw> + %storage)<nsw> LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT:    --> ((4 * (sext i32 %rem to i64))<nsw> + %storage)<nsw> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %1 = load i32, i32* %arrayidx, align 4
 ; CHECK-NEXT:    --> %1 U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %call = call i32 @_Z3adji(i32 %1)
 ; CHECK-NEXT:    --> %call U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %2 = load i32, i32* %arrayidx, align 4
 ; CHECK-NEXT:    --> %2 U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %add = add nsw i32 %2, %call
 ; CHECK-NEXT:    --> (%2 + %call) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }

llvm/test/Analysis/ScalarEvolution/srem.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
 ; RUN: opt < %s -scalar-evolution -analyze | FileCheck %s
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 define dso_local void @_Z4loopi(i32 %width) local_unnamed_addr #0 {
 ; CHECK-LABEL: '_Z4loopi'
 ; CHECK-NEXT:  Classifying expressions for: @_Z4loopi
 ; CHECK-NEXT:    %storage = alloca [2 x i32], align 4
 ; CHECK-NEXT:    --> %storage U: [0,-3) S: [-9223372036854775808,9223372036854775805)
 ; CHECK-NEXT:    %0 = bitcast [2 x i32]* %storage to i8*
 ; CHECK-NEXT:    --> %storage U: [0,-3) S: [-9223372036854775808,9223372036854775805)
 ; CHECK-NEXT:    %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
 ; CHECK-NEXT:    --> {0,+,1}<nuw><nsw><%for.cond> U: [0,-2147483648) S: [0,-2147483648) Exits: %width LoopDispositions: { %for.cond: Computable }
 ; CHECK-NEXT:    %rem = srem i32 %i.0, 2
-; CHECK-NEXT:    --> (zext i1 {false,+,true}<%for.cond> to i32) U: [0,2) S: [0,2) Exits: (zext i1 (trunc i32 %width to i1) to i32) LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT:    --> %rem U: [0,2) S: [-2,2) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %idxprom = sext i32 %rem to i64
-; CHECK-NEXT:    --> (zext i1 {false,+,true}<%for.cond> to i64) U: [0,2) S: [0,2) Exits: (zext i1 (trunc i32 %width to i1) to i64) LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT:    --> (sext i32 %rem to i64) U: [0,2) S: [-2,2) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* %storage, i64 0, i64 %idxprom
-; CHECK-NEXT:    --> ((4 * (zext i1 {false,+,true}<%for.cond> to i64))<nuw><nsw> + %storage)<nsw> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: ((4 * (zext i1 (trunc i32 %width to i1) to i64))<nuw><nsw> + %storage)<nsw> LoopDispositions: { %for.cond: Computable }
+; CHECK-NEXT:    --> ((4 * (sext i32 %rem to i64))<nuw><nsw> + %storage)<nsw> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %1 = load i32, i32* %arrayidx, align 4
 ; CHECK-NEXT:    --> %1 U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %call = call i32 @_Z3adji(i32 %1)
 ; CHECK-NEXT:    --> %call U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %2 = load i32, i32* %arrayidx, align 4
 ; CHECK-NEXT:    --> %2 U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
 ; CHECK-NEXT:    %add = add nsw i32 %2, %call
 ; CHECK-NEXT:    --> (%2 + %call) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }