[ValueTracking] Use `KnownBits::sdiv` for `sdiv` opcode in `computeKnownBits`

[goldstein.w.n]

Summary

We now of an implementation of KnownBits::sdiv so we can implement
this case.

[RKSimon]

LGTM

[goldstein.w.n]

Rebase

[goldstein.w.n]

Rebase

[goldstein.w.n]

Rebase

llvm/lib/Analysis/ValueTracking.cpp

static void computeKnownBitsFromOperator(const Operator *I,
   }
   case Instruction::UDiv: {
     computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
     computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
     Known =
         KnownBits::udiv(Known, Known2, Q.IIQ.isExact(cast<BinaryOperator>(I)));
     break;
   }
+  case Instruction::SDiv: {
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+    Known =
+        KnownBits::sdiv(Known, Known2, Q.IIQ.isExact(cast<BinaryOperator>(I)));
+    break;
+  }
   case Instruction::Select: {
     const Value *LHS = nullptr, *RHS = nullptr;
     SelectPatternFlavor SPF = matchSelectPattern(I, LHS, RHS).Flavor;
     if (SelectPatternResult::isMinOrMax(SPF)) {
       computeKnownBits(RHS, Known, Depth + 1, Q);
       computeKnownBits(LHS, Known2, Depth + 1, Q);
       switch (SPF) {
       default:

llvm/test/Analysis/ValueTracking/knownbits-div.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -passes=instsimplify -S < %s | FileCheck %s
 
 define i1 @sdiv_neg_neg_high_bits(i8 %x, i8 %y) {
 ; CHECK-LABEL: @sdiv_neg_neg_high_bits(
-; CHECK-NEXT:    [[NUM:%.*]] = or i8 [[X:%.*]], -128
-; CHECK-NEXT:    [[DENUM:%.*]] = or i8 [[Y:%.*]], -125
-; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[NUM]], [[DENUM]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DIV]], -128
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], -128
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %num = or i8 %x, 128
   %denum = or i8 %y, 131
   %div = sdiv i8 %num, %denum
   %and = and i8 %div, 128
   %r = icmp eq i8 %and, 128
   ret i1 %r
 }
 
 define i1 @sdiv_pos_neg_high_bits(i8 %x, i8 %y) {
 ; CHECK-LABEL: @sdiv_pos_neg_high_bits(
-; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 127
-; CHECK-NEXT:    [[NUM:%.*]] = or i8 [[XX]], 49
-; CHECK-NEXT:    [[DENUM:%.*]] = or i8 [[Y:%.*]], -15
-; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[NUM]], [[DENUM]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DIV]], -128
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %xx = and i8 %x, 127
   %num = or i8 %xx, 49
   %denum = or i8 %y, 241
   %div = sdiv i8 %num, %denum
   %and = and i8 %div, 128
   %r = icmp eq i8 %and, 0
   ret i1 %r
;
   %div = sdiv i8 %num, %denum
   %and = and i8 %div, 128
   %r = icmp eq i8 %and, 0
   ret i1 %r
 }
 
 define i1 @sdiv_exact_pos_neg_high_bits(i8 %x, i8 %y) {
 ; CHECK-LABEL: @sdiv_exact_pos_neg_high_bits(
-; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 127
-; CHECK-NEXT:    [[NUM:%.*]] = or i8 [[XX]], 49
-; CHECK-NEXT:    [[DENUM:%.*]] = or i8 [[Y:%.*]], -64
-; CHECK-NEXT:    [[DIV:%.*]] = sdiv exact i8 [[NUM]], [[DENUM]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DIV]], -128
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %xx = and i8 %x, 127
   %num = or i8 %xx, 49
   %denum = or i8 %y, 192
   %div = sdiv exact i8 %num, %denum
   %and = and i8 %div, 128
   %r = icmp eq i8 %and, 0
   ret i1 %r
 }
 
 define i1 @sdiv_neg_pos_high_bits(i8 %x, i8 %y) {
 ; CHECK-LABEL: @sdiv_neg_pos_high_bits(
-; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], -97
-; CHECK-NEXT:    [[NUM:%.*]] = or i8 [[XX]], -127
-; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 15
-; CHECK-NEXT:    [[DENUM:%.*]] = or i8 [[YY]], 9
-; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[NUM]], [[DENUM]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DIV]], -128
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %xx = and i8 %x, 159
   %num = or i8 %xx, 129
   %yy = and i8 %y, 15
   %denum = or i8 %yy, 9
   %div = sdiv i8 %num, %denum
   %and = and i8 %div, 128
   %r = icmp eq i8 %and, 0
;
   %div = sdiv i8 %num, %denum
   %and = and i8 %div, 128
   %r = icmp eq i8 %and, 0
   ret i1 %r
 }
 
 define i1 @sdiv_exact_odd_odd(i8 %x, i8 %y) {
 ; CHECK-LABEL: @sdiv_exact_odd_odd(
-; CHECK-NEXT:    [[NUM:%.*]] = or i8 [[X:%.*]], 1
-; CHECK-NEXT:    [[DENUM:%.*]] = or i8 [[Y:%.*]], 1
-; CHECK-NEXT:    [[DIV:%.*]] = sdiv exact i8 [[NUM]], [[DENUM]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DIV]], 1
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %num = or i8 %x, 1
   %denum = or i8 %y, 1
   %div = sdiv exact i8 %num, %denum
   %and = and i8 %div, 1
   %r = icmp eq i8 %and, 0
   ret i1 %r
 }
 
 define i1 @sdiv_exact_even_odd(i8 %x, i8 %y) {
 ; CHECK-LABEL: @sdiv_exact_even_odd(
-; CHECK-NEXT:    [[NUM:%.*]] = and i8 [[X:%.*]], -2
-; CHECK-NEXT:    [[DENUM:%.*]] = or i8 [[Y:%.*]], 1
-; CHECK-NEXT:    [[DIV:%.*]] = sdiv exact i8 [[NUM]], [[DENUM]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DIV]], 1
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 1
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %num = and i8 %x, -2
   %denum = or i8 %y, 1
   %div = sdiv exact i8 %num, %denum
   %and = and i8 %div, 1
   %r = icmp eq i8 %and, 1
   ret i1 %r
 }