[llvm] goldsteinn/track disjoint or (PR #86302)

[via llvm-commits]

https://github.com/goldsteinn created https://github.com/llvm/llvm-project/pull/86302

- **[ValueTracking] Add basic tests tracking `or disjoint` conditions as `add`; NFC**
- **[ValueTracking] Tracking `or disjoint` conditions as `add` in Assumption/DomCondition Cache**


>From 1b1e481b08718fd08700e9640a62a773bd4ea255 Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n at gmail.com>
Date: Wed, 20 Mar 2024 21:01:35 -0500
Subject: [PATCH 1/2] [ValueTracking] Add basic tests tracking `or disjoint`
 conditions as `add`; NFC

---
 .../test/Transforms/InstCombine/known-bits.ll | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/llvm/test/Transforms/InstCombine/known-bits.ll b/llvm/test/Transforms/InstCombine/known-bits.ll
index 58c283815cf910..ff7b81b2f2b25d 100644
--- a/llvm/test/Transforms/InstCombine/known-bits.ll
+++ b/llvm/test/Transforms/InstCombine/known-bits.ll
@@ -483,5 +483,57 @@ if.else:
   ret i64 13
 }
 
+define i1 @test_icmp_or_distjoint(i8 %n, i1 %other) {
+; CHECK-LABEL: @test_icmp_or_distjoint(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[N_OR:%.*]] = or disjoint i8 [[N:%.*]], 16
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i8 [[N_OR]], -111
+; CHECK-NEXT:    br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK:       if.then:
+; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[N]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+; CHECK:       if.else:
+; CHECK-NEXT:    ret i1 [[OTHER:%.*]]
+;
+entry:
+  %n_or = or disjoint i8 %n, 16
+  %cmp = icmp ugt i8 %n_or, 145
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+  %r = icmp slt i8 %n, 0
+  ret i1 %r
+
+if.else:
+  ret i1 %other
+}
+
+define i1 @test_icmp_or_fail_missing_disjoint(i8 %n, i1 %other) {
+; CHECK-LABEL: @test_icmp_or_fail_missing_disjoint(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[N_OR:%.*]] = or i8 [[N:%.*]], 16
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i8 [[N_OR]], -111
+; CHECK-NEXT:    br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK:       if.then:
+; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[N]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+; CHECK:       if.else:
+; CHECK-NEXT:    ret i1 [[OTHER:%.*]]
+;
+entry:
+  %n_or = or i8 %n, 16
+  %cmp = icmp ugt i8 %n_or, 145
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+  %r = icmp slt i8 %n, 0
+  ret i1 %r
+
+if.else:
+  ret i1 %other
+}
+
+
+
 declare void @use(i1)
 declare void @sink(i8)

>From 6dd200406a703e2a4c3c567644deb3c65c188a72 Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n at gmail.com>
Date: Wed, 20 Mar 2024 20:12:21 -0500
Subject: [PATCH 2/2] [ValueTracking] Tracking `or disjoint` conditions as
 `add` in Assumption/DomCondition Cache

We can definitionally treat `or disjoint` as `add` anywhere.
---
 llvm/lib/Analysis/ValueTracking.cpp            | 4 ++--
 llvm/test/Transforms/InstCombine/known-bits.ll | 3 +--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 797665cf06c875..b5e8a1d22f264b 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -699,7 +699,7 @@ static void computeKnownBitsFromCmp(const Value *V, CmpInst::Predicate Pred,
   }
   default:
     const APInt *Offset = nullptr;
-    if (match(LHS, m_CombineOr(m_V, m_Add(m_V, m_APInt(Offset)))) &&
+    if (match(LHS, m_CombineOr(m_V, m_AddLike(m_V, m_APInt(Offset)))) &&
         match(RHS, m_APInt(C))) {
       ConstantRange LHSRange = ConstantRange::makeAllowedICmpRegion(Pred, *C);
       if (Offset)
@@ -9285,7 +9285,7 @@ void llvm::findValuesAffectedByCondition(
       } else {
         // Handle (A + C1) u< C2, which is the canonical form of
         // A > C3 && A < C4.
-        if (match(A, m_Add(m_Value(X), m_ConstantInt())) &&
+        if (match(A, m_AddLike(m_Value(X), m_ConstantInt())) &&
             match(B, m_ConstantInt()))
           AddAffected(X);
 
diff --git a/llvm/test/Transforms/InstCombine/known-bits.ll b/llvm/test/Transforms/InstCombine/known-bits.ll
index ff7b81b2f2b25d..5305c78f691231 100644
--- a/llvm/test/Transforms/InstCombine/known-bits.ll
+++ b/llvm/test/Transforms/InstCombine/known-bits.ll
@@ -490,8 +490,7 @@ define i1 @test_icmp_or_distjoint(i8 %n, i1 %other) {
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i8 [[N_OR]], -111
 ; CHECK-NEXT:    br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
 ; CHECK:       if.then:
-; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[N]], 0
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       if.else:
 ; CHECK-NEXT:    ret i1 [[OTHER:%.*]]
 ;