[llvm] 124547e - [ValueTracking] Use `KnownBits::sdiv` for `sdiv` opcode in `computeKnownBits`

[Noah Goldstein via llvm-commits]

Author: Noah Goldstein
Date: 2023-05-16T18:58:12-05:00
New Revision: 124547eae8a610a9a77fe3e219e9cd98a2580cfe

URL: https://github.com/llvm/llvm-project/commit/124547eae8a610a9a77fe3e219e9cd98a2580cfe
DIFF: https://github.com/llvm/llvm-project/commit/124547eae8a610a9a77fe3e219e9cd98a2580cfe.diff

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

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

Differential Revision: https://reviews.llvm.org/D150096

Added: 
    

Modified: 
    llvm/lib/Analysis/ValueTracking.cpp
    llvm/test/Analysis/ValueTracking/knownbits-div.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 77b99f9e818c..0368c090665f 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1212,6 +1212,13 @@ static void computeKnownBitsFromOperator(const Operator *I,
         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;

diff  --git a/llvm/test/Analysis/ValueTracking/knownbits-div.ll b/llvm/test/Analysis/ValueTracking/knownbits-div.ll
index 15e1ac90eda0..e1e17d30b542 100644
--- a/llvm/test/Analysis/ValueTracking/knownbits-div.ll
+++ b/llvm/test/Analysis/ValueTracking/knownbits-div.ll
@@ -3,12 +3,7 @@
 
 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
@@ -20,13 +15,7 @@ define i1 @sdiv_neg_neg_high_bits(i8 %x, i8 %y) {
 
 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
@@ -58,13 +47,7 @@ define i1 @sdiv_pos_neg_high_bits_fail_maybez(i8 %x, i8 %y) {
 
 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
@@ -77,14 +60,7 @@ define i1 @sdiv_exact_pos_neg_high_bits(i8 %x, i8 %y) {
 
 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
@@ -117,12 +93,7 @@ define i1 @sdiv_neg_pos_high_bits_fail_maybez(i8 %x, i8 %y) {
 
 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
@@ -134,12 +105,7 @@ define i1 @sdiv_exact_odd_odd(i8 %x, i8 %y) {
 
 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