[llvm] 6063e3c - [ValueTracking] Implement `computeKnownBits` for `llvm.vector.reduce.{or,and}`

[Noah Goldstein via llvm-commits]

Author: Noah Goldstein
Date: 2024-04-14T22:49:05-05:00
New Revision: 6063e3c40867e9b9865aee326ff36cb2ebbcf939

URL: https://github.com/llvm/llvm-project/commit/6063e3c40867e9b9865aee326ff36cb2ebbcf939
DIFF: https://github.com/llvm/llvm-project/commit/6063e3c40867e9b9865aee326ff36cb2ebbcf939.diff

LOG: [ValueTracking] Implement `computeKnownBits` for `llvm.vector.reduce.{or,and}`

Added: 
    

Modified: 
    llvm/lib/Analysis/ValueTracking.cpp
    llvm/test/Transforms/InstCombine/known-bits.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index b83e7e6769c200..359a9dc7907b7e 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1624,8 +1624,10 @@ static void computeKnownBitsFromOperator(const Operator *I,
         computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
         Known = KnownBits::ssub_sat(Known, Known2);
         break;
-        // for min/max reduce, any bit common to each element in the input vec
-        // is set in the output.
+        // for min/max/and/or reduce, any bit common to each element in the
+        // input vec is set in the output.
+      case Intrinsic::vector_reduce_and:
+      case Intrinsic::vector_reduce_or:
       case Intrinsic::vector_reduce_umax:
       case Intrinsic::vector_reduce_umin:
       case Intrinsic::vector_reduce_smax:

diff  --git a/llvm/test/Transforms/InstCombine/known-bits.ll b/llvm/test/Transforms/InstCombine/known-bits.ll
index cdc3e991a3fb5a..ce415dd406c05c 100644
--- a/llvm/test/Transforms/InstCombine/known-bits.ll
+++ b/llvm/test/Transforms/InstCombine/known-bits.ll
@@ -1197,10 +1197,7 @@ define i1 @extract_value_smul_fail(i8 %xx, i8 %yy) {
 
 define i8 @known_reduce_or(<2 x i8> %xx) {
 ; CHECK-LABEL: @known_reduce_or(
-; CHECK-NEXT:    [[X:%.*]] = or <2 x i8> [[XX:%.*]], <i8 5, i8 3>
-; CHECK-NEXT:    [[V:%.*]] = call i8 @llvm.vector.reduce.or.v2i8(<2 x i8> [[X]])
-; CHECK-NEXT:    [[R:%.*]] = and i8 [[V]], 1
-; CHECK-NEXT:    ret i8 [[R]]
+; CHECK-NEXT:    ret i8 1
 ;
   %x = or <2 x i8> %xx, <i8 5, i8 3>
   %v = call i8 @llvm.vector.reduce.or(<2 x i8> %x)
@@ -1223,10 +1220,7 @@ define i8 @known_reduce_or_fail(<2 x i8> %xx) {
 
 define i8 @known_reduce_and(<2 x i8> %xx) {
 ; CHECK-LABEL: @known_reduce_and(
-; CHECK-NEXT:    [[X:%.*]] = or <2 x i8> [[XX:%.*]], <i8 5, i8 3>
-; CHECK-NEXT:    [[V:%.*]] = call i8 @llvm.vector.reduce.or.v2i8(<2 x i8> [[X]])
-; CHECK-NEXT:    [[R:%.*]] = and i8 [[V]], 1
-; CHECK-NEXT:    ret i8 [[R]]
+; CHECK-NEXT:    ret i8 1
 ;
   %x = or <2 x i8> %xx, <i8 5, i8 3>
   %v = call i8 @llvm.vector.reduce.or(<2 x i8> %x)