[IPSCCP] Intersect attribute info for interprocedural args (#106397)

IPSCCP can currently return worse results than SCCP for arguments that
are tracked interprocedurally, because information from attributes is
not used for them.

Fix this by intersecting in the attribute information when propagating
lattice values from calls.

Author: nikic

llvm/lib/Transforms/Utils/SCCPSolver.cpp

@@ -820,19 +820,21 @@ class SCCPInstVisitor : public InstVisitor<SCCPInstVisitor> {
       markOverdefined(ValueState[V], V);
   }
 
-  void trackValueOfArgument(Argument *A) {
+  ValueLatticeElement getArgAttributeVL(Argument *A) {
     if (A->getType()->isIntOrIntVectorTy()) {
-      if (std::optional<ConstantRange> Range = A->getRange()) {
-        markConstantRange(ValueState[A], A, *Range);
-        return;
-      }
-    }
-    if (A->hasNonNullAttr()) {
-      markNotNull(ValueState[A], A);
-      return;
+      if (std::optional<ConstantRange> Range = A->getRange())
+        return ValueLatticeElement::getRange(*Range);
     }
+    if (A->hasNonNullAttr())
+      return ValueLatticeElement::getNot(Constant::getNullValue(A->getType()));
     // Assume nothing about the incoming arguments without attributes.
-    markOverdefined(A);
+    return ValueLatticeElement::getOverdefined();
+  }
+
+  void trackValueOfArgument(Argument *A) {
+    if (A->getType()->isStructTy())
+      return (void)markOverdefined(A);
+    mergeInValue(A, getArgAttributeVL(A));
   }
 
   bool isStructLatticeConstant(Function *F, StructType *STy);
@@ -1800,7 +1802,9 @@ void SCCPInstVisitor::handleCallArguments(CallBase &CB) {
                        getMaxWidenStepsOpts());
         }
       } else
-        mergeInValue(&*AI, getValueState(*CAI), getMaxWidenStepsOpts());
+        mergeInValue(&*AI,
+                     getValueState(*CAI).intersect(getArgAttributeVL(&*AI)),
+                     getMaxWidenStepsOpts());
     }
   }
 }

llvm/test/Transforms/SCCP/pointer-nonnull.ll

@@ -210,18 +210,22 @@ define internal i1 @ip_test_nonnull_callee(ptr nonnull %p) {
 ;
 ; IPSCCP-LABEL: define internal i1 @ip_test_nonnull_callee(
 ; IPSCCP-SAME: ptr nonnull [[P:%.*]]) {
-; IPSCCP-NEXT:    [[CMP:%.*]] = icmp ne ptr [[P]], null
-; IPSCCP-NEXT:    ret i1 [[CMP]]
+; IPSCCP-NEXT:    ret i1 poison
 ;
   %cmp = icmp ne ptr %p, null
   ret i1 %cmp
 }
 
 define i1 @ip_test_nonnull_caller(ptr %p) {
-; CHECK-LABEL: define i1 @ip_test_nonnull_caller(
-; CHECK-SAME: ptr [[P:%.*]]) {
-; CHECK-NEXT:    [[RES:%.*]] = call i1 @ip_test_nonnull_callee(ptr [[P]])
-; CHECK-NEXT:    ret i1 [[RES]]
+; SCCP-LABEL: define i1 @ip_test_nonnull_caller(
+; SCCP-SAME: ptr [[P:%.*]]) {
+; SCCP-NEXT:    [[RES:%.*]] = call i1 @ip_test_nonnull_callee(ptr [[P]])
+; SCCP-NEXT:    ret i1 [[RES]]
+;
+; IPSCCP-LABEL: define i1 @ip_test_nonnull_caller(
+; IPSCCP-SAME: ptr [[P:%.*]]) {
+; IPSCCP-NEXT:    [[RES:%.*]] = call i1 @ip_test_nonnull_callee(ptr [[P]])
+; IPSCCP-NEXT:    ret i1 true
 ;
   %res = call i1 @ip_test_nonnull_callee(ptr %p)
   ret i1 %res

llvm/test/Transforms/SCCP/range-attribute.ll

@@ -193,8 +193,7 @@ define i1 @ip_range_attribute_constant() {
 
 define internal i1 @ip_cmp_attribute_overdefined_callee(i32 range(i32 0, 10) %x) {
 ; IPSCCP-LABEL: @ip_cmp_attribute_overdefined_callee(
-; IPSCCP-NEXT:    [[CMP:%.*]] = icmp ult i32 [[X:%.*]], 10
-; IPSCCP-NEXT:    ret i1 [[CMP]]
+; IPSCCP-NEXT:    ret i1 poison
 ;
 ; SCCP-LABEL: @ip_cmp_attribute_overdefined_callee(
 ; SCCP-NEXT:    ret i1 true
@@ -204,19 +203,21 @@ define internal i1 @ip_cmp_attribute_overdefined_callee(i32 range(i32 0, 10) %x)
 }
 
 define i1 @ip_cmp_attribute_overdefined_caller(i32 %x) {
-; CHECK-LABEL: @ip_cmp_attribute_overdefined_caller(
-; CHECK-NEXT:    [[RES:%.*]] = call i1 @ip_cmp_attribute_overdefined_callee(i32 [[X:%.*]])
-; CHECK-NEXT:    ret i1 [[RES]]
+; IPSCCP-LABEL: @ip_cmp_attribute_overdefined_caller(
+; IPSCCP-NEXT:    [[RES:%.*]] = call i1 @ip_cmp_attribute_overdefined_callee(i32 [[X:%.*]])
+; IPSCCP-NEXT:    ret i1 true
+;
+; SCCP-LABEL: @ip_cmp_attribute_overdefined_caller(
+; SCCP-NEXT:    [[RES:%.*]] = call i1 @ip_cmp_attribute_overdefined_callee(i32 [[X:%.*]])
+; SCCP-NEXT:    ret i1 [[RES]]
 ;
   %res = call i1 @ip_cmp_attribute_overdefined_callee(i32 %x)
   ret i1 %res
 }
 
 define internal i1 @ip_cmp_attribute_intersect_callee(i32 range(i32 0, 10) %x) {
 ; IPSCCP-LABEL: @ip_cmp_attribute_intersect_callee(
-; IPSCCP-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], 10
-; IPSCCP-NEXT:    [[AND:%.*]] = and i1 [[CMP1]], true
-; IPSCCP-NEXT:    ret i1 [[AND]]
+; IPSCCP-NEXT:    ret i1 poison
 ;
 ; SCCP-LABEL: @ip_cmp_attribute_intersect_callee(
 ; SCCP-NEXT:    [[CMP2:%.*]] = icmp uge i32 [[X:%.*]], 5
@@ -230,9 +231,13 @@ define internal i1 @ip_cmp_attribute_intersect_callee(i32 range(i32 0, 10) %x) {
 }
 
 define i1 @ip_cmp_attribute_intersect_caller(i32 range(i32 5, 15) %x) {
-; CHECK-LABEL: @ip_cmp_attribute_intersect_caller(
-; CHECK-NEXT:    [[RES:%.*]] = call i1 @ip_cmp_attribute_intersect_callee(i32 [[X:%.*]])
-; CHECK-NEXT:    ret i1 [[RES]]
+; IPSCCP-LABEL: @ip_cmp_attribute_intersect_caller(
+; IPSCCP-NEXT:    [[RES:%.*]] = call i1 @ip_cmp_attribute_intersect_callee(i32 [[X:%.*]])
+; IPSCCP-NEXT:    ret i1 true
+;
+; SCCP-LABEL: @ip_cmp_attribute_intersect_caller(
+; SCCP-NEXT:    [[RES:%.*]] = call i1 @ip_cmp_attribute_intersect_callee(i32 [[X:%.*]])
+; SCCP-NEXT:    ret i1 [[RES]]
 ;
   %res = call i1 @ip_cmp_attribute_intersect_callee(i32 %x)
   ret i1 %res