From b5ddcb9f1e41b142f89110fc9be78b3c6997f090 Mon Sep 17 00:00:00 2001
From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Thu, 7 Nov 2019 01:16:01 +0300
Subject: [PATCH] [ConstantRange] TestAddWithNo*WrapExhaustive: check that all
 overflow means empty set

As disscussed in https://reviews.llvm.org/D69918 / https://reviews.llvm.org/D67339
that is an implied postcondition, but it's not really fully tested.
---
 llvm/unittests/IR/ConstantRangeTest.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/llvm/unittests/IR/ConstantRangeTest.cpp b/llvm/unittests/IR/ConstantRangeTest.cpp
index 742c5fa..eb79711 100644
--- a/llvm/unittests/IR/ConstantRangeTest.cpp
+++ b/llvm/unittests/IR/ConstantRangeTest.cpp
@@ -651,11 +651,13 @@ static void TestAddWithNoSignedWrapExhaustive(Fn1 RangeFn, Fn2 IntFn) {
     ConstantRange CR = RangeFn(CR1, CR2);
     APInt Min = APInt::getSignedMaxValue(Bits);
     APInt Max = APInt::getSignedMinValue(Bits);
+    bool AllOverflow = true;
     ForeachNumInConstantRange(CR1, [&](const APInt &N1) {
       ForeachNumInConstantRange(CR2, [&](const APInt &N2) {
         bool IsOverflow = false;
         APInt N = IntFn(IsOverflow, N1, N2);
         if (!IsOverflow) {
+          AllOverflow = false;
           if (N.slt(Min))
             Min = N;
           if (N.sgt(Max))
@@ -664,6 +666,9 @@ static void TestAddWithNoSignedWrapExhaustive(Fn1 RangeFn, Fn2 IntFn) {
         }
       });
     });
+
+    EXPECT_EQ(CR.isEmptySet(), AllOverflow);
+
     if (!CR1.isSignWrappedSet() && !CR2.isSignWrappedSet()) {
       if (Min.sgt(Max)) {
         EXPECT_TRUE(CR.isEmptySet());
@@ -684,11 +689,13 @@ static void TestAddWithNoUnsignedWrapExhaustive(Fn1 RangeFn, Fn2 IntFn) {
     ConstantRange CR = RangeFn(CR1, CR2);
     APInt Min = APInt::getMaxValue(Bits);
     APInt Max = APInt::getMinValue(Bits);
+    bool AllOverflow = true;
     ForeachNumInConstantRange(CR1, [&](const APInt &N1) {
       ForeachNumInConstantRange(CR2, [&](const APInt &N2) {
         bool IsOverflow = false;
         APInt N = IntFn(IsOverflow, N1, N2);
         if (!IsOverflow) {
+          AllOverflow = false;
           if (N.ult(Min))
             Min = N;
           if (N.ugt(Max))
@@ -698,6 +705,8 @@ static void TestAddWithNoUnsignedWrapExhaustive(Fn1 RangeFn, Fn2 IntFn) {
       });
     });
 
+    EXPECT_EQ(CR.isEmptySet(), AllOverflow);
+
     if (!CR1.isWrappedSet() && !CR2.isWrappedSet()) {
       if (Min.ugt(Max)) {
         EXPECT_TRUE(CR.isEmptySet());
@@ -722,12 +731,14 @@ static void TestAddWithNoSignedUnsignedWrapExhaustive(Fn1 RangeFn,
         APInt UMax = APInt::getMinValue(Bits);
         APInt SMin = APInt::getSignedMaxValue(Bits);
         APInt SMax = APInt::getSignedMinValue(Bits);
+        bool AllOverflow = true;
         ForeachNumInConstantRange(CR1, [&](const APInt &N1) {
           ForeachNumInConstantRange(CR2, [&](const APInt &N2) {
             bool IsOverflow = false, IsSignedOverflow = false;
             APInt N = IntFnSigned(IsSignedOverflow, N1, N2);
             (void) IntFnUnsigned(IsOverflow, N1, N2);
             if (!IsSignedOverflow && !IsOverflow) {
+              AllOverflow = false;
               if (N.slt(SMin))
                 SMin = N;
               if (N.sgt(SMax))
@@ -741,6 +752,8 @@ static void TestAddWithNoSignedUnsignedWrapExhaustive(Fn1 RangeFn,
           });
         });
 
+        EXPECT_EQ(CR.isEmptySet(), AllOverflow);
+
         if (!CR1.isWrappedSet() && !CR2.isWrappedSet() &&
             !CR1.isSignWrappedSet() && !CR2.isSignWrappedSet()) {
           if (UMin.ugt(UMax) || SMin.sgt(SMax)) {
-- 
2.7.4