[LVI] Support no constant range of cast value in getEdgeValueLocal. (#157614)

proof: https://alive2.llvm.org/ce/z/8emkHY

Author: andjo403

llvm/lib/Analysis/LazyValueInfo.cpp

@@ -1493,6 +1493,24 @@ LazyValueInfoImpl::getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
             //   br %Condition, label %then, label %else
             APInt ConditionVal(1, isTrueDest ? 1 : 0);
             Result = constantFoldUser(Usr, Condition, ConditionVal, DL);
+          } else if (isa<TruncInst, ZExtInst, SExtInst>(Usr)) {
+            ValueLatticeElement OpLatticeVal =
+                *getValueFromCondition(Usr->getOperand(0), Condition,
+                                       isTrueDest, /*UseBlockValue*/ false);
+
+            if (!OpLatticeVal.isConstantRange())
+              return OpLatticeVal;
+
+            const unsigned ResultBitWidth =
+                Usr->getType()->getScalarSizeInBits();
+            if (auto *Trunc = dyn_cast<TruncInst>(Usr))
+              return ValueLatticeElement::getRange(
+                  OpLatticeVal.getConstantRange().truncate(
+                      ResultBitWidth, Trunc->getNoWrapKind()));
+
+            return ValueLatticeElement::getRange(
+                OpLatticeVal.getConstantRange().castOp(
+                    cast<CastInst>(Usr)->getOpcode(), ResultBitWidth));
           } else {
             // If one of Val's operand has an inferred value, we may be able to
             // infer the value of Val.

llvm/test/Transforms/CorrelatedValuePropagation/range.ll

@@ -1235,6 +1235,126 @@ define i1 @neg_icmp_eq_range_call() {
   ret i1 %cmp
 }
 
+define i16 @return_range_for_edge_value_zext(i8 %a) {
+; CHECK-LABEL: define range(i16 0, 98) i16 @return_range_for_edge_value_zext(
+; CHECK-SAME: i8 [[A:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[B:%.*]] = zext i8 [[A]] to i16
+; CHECK-NEXT:    br label %[[DISPATCH:.*]]
+; CHECK:       [[DISPATCH]]:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i8 [[A]], 98
+; CHECK-NEXT:    br i1 [[CMP]], label %[[TARGET:.*]], label %[[DISPATCH]]
+; CHECK:       [[TARGET]]:
+; CHECK-NEXT:    ret i16 [[B]]
+;
+entry:
+  %b = zext i8 %a to i16
+  br label %dispatch
+
+dispatch:
+  %cmp = icmp ult i8 %a, 98
+  br i1 %cmp, label %target, label %dispatch
+
+target:
+  ret i16 %b
+}
+
+define i16 @return_range_for_edge_value_sext(i8 %a) {
+; CHECK-LABEL: define range(i16 -55, 0) i16 @return_range_for_edge_value_sext(
+; CHECK-SAME: i8 [[A:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[B:%.*]] = sext i8 [[A]] to i16
+; CHECK-NEXT:    br label %[[DISPATCH:.*]]
+; CHECK:       [[DISPATCH]]:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i8 [[A]], -56
+; CHECK-NEXT:    br i1 [[CMP]], label %[[TARGET:.*]], label %[[DISPATCH]]
+; CHECK:       [[TARGET]]:
+; CHECK-NEXT:    ret i16 [[B]]
+;
+entry:
+  %b = sext i8 %a to i16
+  br label %dispatch
+
+dispatch:
+  %cmp = icmp ugt i8 %a, -56
+  br i1 %cmp, label %target, label %dispatch
+
+target:
+  ret i16 %b
+}
+
+define i8 @return_range_for_edge_value_trunc(i16 %a) {
+; CHECK-LABEL: define range(i8 0, 98) i8 @return_range_for_edge_value_trunc(
+; CHECK-SAME: i16 [[A:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[B:%.*]] = trunc i16 [[A]] to i8
+; CHECK-NEXT:    br label %[[DISPATCH:.*]]
+; CHECK:       [[DISPATCH]]:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i16 [[A]], 98
+; CHECK-NEXT:    br i1 [[CMP]], label %[[TARGET:.*]], label %[[DISPATCH]]
+; CHECK:       [[TARGET]]:
+; CHECK-NEXT:    ret i8 [[B]]
+;
+entry:
+  %b = trunc i16 %a to i8
+  br label %dispatch
+
+dispatch:
+  %cmp = icmp ult i16 %a, 98
+  br i1 %cmp, label %target, label %dispatch
+
+target:
+  ret i8 %b
+}
+
+define i8 @neg_return_range_for_edge_value_trunc(i16 %a) {
+; CHECK-LABEL: define i8 @neg_return_range_for_edge_value_trunc(
+; CHECK-SAME: i16 [[A:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[B:%.*]] = trunc i16 [[A]] to i8
+; CHECK-NEXT:    br label %[[DISPATCH:.*]]
+; CHECK:       [[DISPATCH]]:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i16 [[A]], 200
+; CHECK-NEXT:    br i1 [[CMP]], label %[[TARGET:.*]], label %[[DISPATCH]]
+; CHECK:       [[TARGET]]:
+; CHECK-NEXT:    ret i8 [[B]]
+;
+entry:
+  %b = trunc i16 %a to i8
+  br label %dispatch
+
+dispatch:
+  %cmp = icmp ugt i16 %a, 200
+  br i1 %cmp, label %target, label %dispatch
+
+target:
+  ret i8 %b
+}
+
+define i8 @return_range_for_edge_value_trunc_nuw(i16 %a) {
+; CHECK-LABEL: define range(i8 -55, 0) i8 @return_range_for_edge_value_trunc_nuw(
+; CHECK-SAME: i16 [[A:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[B:%.*]] = trunc nuw i16 [[A]] to i8
+; CHECK-NEXT:    br label %[[DISPATCH:.*]]
+; CHECK:       [[DISPATCH]]:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i16 [[A]], 200
+; CHECK-NEXT:    br i1 [[CMP]], label %[[TARGET:.*]], label %[[DISPATCH]]
+; CHECK:       [[TARGET]]:
+; CHECK-NEXT:    ret i8 [[B]]
+;
+entry:
+  %b = trunc nuw i16 %a to i8
+  br label %dispatch
+
+dispatch:
+  %cmp = icmp ugt i16 %a, 200
+  br i1 %cmp, label %target, label %dispatch
+
+target:
+  ret i8 %b
+}
+
 declare i16 @llvm.ctlz.i16(i16, i1)
 declare i16 @llvm.cttz.i16(i16, i1)
 declare i16 @llvm.ctpop.i16(i16)

llvm/test/Transforms/JumpThreading/branch-debug-info2.ll

@@ -18,8 +18,8 @@ if.end.i60:                                       ; preds = %shadow_to_ptr.exit
   %spec.select.i = select i1 %cmp3.i, i32 -1, i32 %conv7.i, !dbg !17
 ; Jump threading is going to fold the select in to the branch. Ensure debug
 ; info is not lost, and is merged from the select and the branch.
-; CHECK-NOT: br i1 %cmp3.i, label %for.inc, label %ptr_to_shadow.exit
-; CHECK: br i1 %cmp3.i, label %for.inc, label %ptr_to_shadow.exit, !dbg [[DBG:![0-9]+]]
+; CHECK-NOT: br i1 %cmp3.i, label %for.inc, label %if.end22
+; CHECK: br i1 %cmp3.i, label %for.inc, label %if.end22, !dbg [[DBG:![0-9]+]]
 ; CHECK: [[DBG]] = !DILocation(line: 9, column: 1, scope: !{{.*}})
 
   br label %ptr_to_shadow.exit, !dbg !17