[SCEV] Mark AddExprs as nsw or nuw if legal

Summary:
This uses `ScalarEvolution::getRange` and not potentially control
dependent `nsw` and `nuw` bits on the arithmetic instruction.

Reviewers: atrick, hfinkel, nlewycky

Subscribers: llvm-commits, sanjoy

Differential Revision: http://reviews.llvm.org/D13613

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251048 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 7e065215cb93960557c04b89adc24d772be0c21d..8a257b46e7edf1823b317358f2f3f001855d1de2 100644 (file)
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -1921,8 +1921,9 @@ namespace {
 static SCEV::NoWrapFlags
 StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type,
                       const SmallVectorImpl<const SCEV *> &Ops,
-                      SCEV::NoWrapFlags OldFlags) {
+                      SCEV::NoWrapFlags Flags) {
   using namespace std::placeholders;
+  typedef OverflowingBinaryOperator OBO;
 
   bool CanAnalyze =
       Type == scAddExpr || Type == scAddRecExpr || Type == scMulExpr;
@@ -1931,7 +1932,7 @@ StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type,
 
   int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW;
   SCEV::NoWrapFlags SignOrUnsignWrap =
-      ScalarEvolution::maskFlags(OldFlags, SignOrUnsignMask);
+      ScalarEvolution::maskFlags(Flags, SignOrUnsignMask);
 
   // If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
   auto IsKnownNonNegative =
@@ -1939,10 +1940,34 @@ StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type,
 
   if (SignOrUnsignWrap == SCEV::FlagNSW &&
       std::all_of(Ops.begin(), Ops.end(), IsKnownNonNegative))
-    return ScalarEvolution::setFlags(OldFlags,
-                                     (SCEV::NoWrapFlags)SignOrUnsignMask);
+    Flags =
+        ScalarEvolution::setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask);
 
-  return OldFlags;
+  SignOrUnsignWrap = ScalarEvolution::maskFlags(Flags, SignOrUnsignMask);
+
+  if (SignOrUnsignWrap != SignOrUnsignMask && Type == scAddExpr &&
+      Ops.size() == 2 && isa<SCEVConstant>(Ops[0])) {
+
+    // (A + C) --> (A + C)<nsw> if the addition does not sign overflow
+    // (A + C) --> (A + C)<nuw> if the addition does not unsign overflow
+
+    const APInt &C = cast<SCEVConstant>(Ops[0])->getValue()->getValue();
+    if (!(SignOrUnsignWrap & SCEV::FlagNSW)) {
+      auto NSWRegion =
+        ConstantRange::makeNoWrapRegion(Instruction::Add, C, OBO::NoSignedWrap);
+      if (NSWRegion.contains(SE->getSignedRange(Ops[1])))
+        Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW);
+    }
+    if (!(SignOrUnsignWrap & SCEV::FlagNUW)) {
+      auto NUWRegion =
+        ConstantRange::makeNoWrapRegion(Instruction::Add, C,
+                                        OBO::NoUnsignedWrap);
+      if (NUWRegion.contains(SE->getUnsignedRange(Ops[1])))
+        Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
+    }
+  }
+
+  return Flags;
 }
 
 /// getAddExpr - Get a canonical add expression, or something simpler if

diff --git a/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_3d.ll b/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_3d.ll
index 4ae976281c44c20145f1b9721ccfd13d7d72992f..79d0c789704b26609ebb79a5c98ccfb94ebd19a3 100644 (file)
--- a/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_3d.ll
+++ b/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_3d.ll
@@ -11,7 +11,7 @@
 ; AddRec: {{{(56 + (8 * (-4 + (3 * %m)) * %o) + %A),+,(8 * %m * %o)}<%for.i>,+,(8 * %o)}<%for.j>,+,8}<%for.k>
 ; CHECK: Base offset: %A
 ; CHECK: ArrayDecl[UnknownSize][%m][%o] with elements of 8 bytes.
-; CHECK: ArrayRef[{3,+,1}<nw><%for.i>][{-4,+,1}<nw><%for.j>][{7,+,1}<nuw><nsw><%for.k>]
+; CHECK: ArrayRef[{3,+,1}<nuw><%for.i>][{-4,+,1}<nw><%for.j>][{7,+,1}<nuw><nsw><%for.k>]
 
 define void @foo(i64 %n, i64 %m, i64 %o, double* %A) {
 entry:

diff --git a/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_nts_3d.ll b/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_nts_3d.ll
index ada7758b21ba7ba13201c77348c333da7c53b0de..f886d2ccd2887723bdcb4394d84797511e092dc0 100644 (file)
--- a/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_nts_3d.ll
+++ b/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_nts_3d.ll
@@ -11,7 +11,7 @@
 ; AddRec: {{{(56 + (8 * (-4 + (3 * %m)) * (%o + %p)) + %A),+,(8 * (%o + %p) * %m)}<%for.cond4.preheader.lr.ph.us>,+,(8 * (%o + %p))}<%for.body6.lr.ph.us.us>,+,8}<%for.body6.us.us>
 ; CHECK: Base offset: %A
 ; CHECK: ArrayDecl[UnknownSize][%m][(%o + %p)] with elements of 8 bytes.
-; CHECK: ArrayRef[{3,+,1}<nw><%for.cond4.preheader.lr.ph.us>][{-4,+,1}<nw><%for.body6.lr.ph.us.us>][{7,+,1}<nw><%for.body6.us.us>]
+; CHECK: ArrayRef[{3,+,1}<nuw><%for.cond4.preheader.lr.ph.us>][{-4,+,1}<nw><%for.body6.lr.ph.us.us>][{7,+,1}<nw><%for.body6.us.us>]
 
 define void @foo(i64 %n, i64 %m, i64 %o, i64 %p, double* nocapture %A) nounwind uwtable {
 entry:

diff --git a/test/Analysis/ScalarEvolution/infer-prestart-no-wrap.ll b/test/Analysis/ScalarEvolution/infer-prestart-no-wrap.ll
index 078ca03ff14e173d7e60cdc68684a814a465410a..5c372b5d7b8a1241659a1538387d97e075951145 100644 (file)
--- a/test/Analysis/ScalarEvolution/infer-prestart-no-wrap.ll
+++ b/test/Analysis/ScalarEvolution/infer-prestart-no-wrap.ll
@@ -11,7 +11,7 @@ define void @infer.sext.0(i1* %c, i32 %start) {
   %idx.inc = add nsw i32 %idx, 1
   %idx.inc.sext = sext i32 %idx.inc to i64
 ; CHECK: %idx.inc.sext = sext i32 %idx.inc to i64
-; CHECK-NEXT: -->  {(1 + (sext i32 %start to i64)),+,1}<nsw><%loop>
+; CHECK-NEXT: -->  {(1 + (sext i32 %start to i64))<nsw>,+,1}<nsw><%loop>
   %condition = icmp eq i32 %counter, 1
   %counter.inc = add i32 %counter, 1
   br i1 %condition, label %exit, label %loop
@@ -31,7 +31,7 @@ define void @infer.zext.0(i1* %c, i32 %start) {
   %idx.inc = add nuw i32 %idx, 1
   %idx.inc.sext = zext i32 %idx.inc to i64
 ; CHECK: %idx.inc.sext = zext i32 %idx.inc to i64
-; CHECK-NEXT: -->  {(1 + (zext i32 %start to i64)),+,1}<nuw><%loop>
+; CHECK-NEXT: -->  {(1 + (zext i32 %start to i64))<nuw><nsw>,+,1}<nuw><%loop>
   %condition = icmp eq i32 %counter, 1
   %counter.inc = add i32 %counter, 1
   br i1 %condition, label %exit, label %loop
@@ -51,7 +51,7 @@ define void @infer.sext.1(i32 %start, i1* %c) {
   %idx = phi i32 [ %start.real, %entry ], [ %idx.inc, %loop ]
   %idx.sext = sext i32 %idx to i64
 ; CHECK: %idx.sext = sext i32 %idx to i64
-; CHECK-NEXT:  -->  {(2 + (sext i32 (4 * %start) to i64)),+,2}<nsw><%loop>
+; CHECK-NEXT:  -->  {(2 + (sext i32 (4 * %start) to i64))<nsw>,+,2}<nsw><%loop>
   %idx.inc = add nsw i32 %idx, 2
   %condition = load i1, i1* %c
   br i1 %condition, label %exit, label %loop
@@ -71,7 +71,7 @@ define void @infer.sext.2(i1* %c, i8 %start) {
   %idx = phi i8 [ %start.inc, %entry ], [ %idx.inc, %loop ]
   %idx.sext = sext i8 %idx to i16
 ; CHECK: %idx.sext = sext i8 %idx to i16
-; CHECK-NEXT: -->  {(1 + (sext i8 %start to i16)),+,1}<nsw><%loop>
+; CHECK-NEXT: -->  {(1 + (sext i8 %start to i16))<nsw>,+,1}<nsw><%loop>
   %idx.inc = add nsw i8 %idx, 1
   %condition = load volatile i1, i1* %c
   br i1 %condition, label %exit, label %loop
@@ -91,7 +91,7 @@ define void @infer.zext.1(i1* %c, i8 %start) {
   %idx = phi i8 [ %start.inc, %entry ], [ %idx.inc, %loop ]
   %idx.zext = zext i8 %idx to i16
 ; CHECK: %idx.zext = zext i8 %idx to i16
-; CHECK-NEXT: -->  {(1 + (zext i8 %start to i16)),+,1}<nuw><%loop>
+; CHECK-NEXT: -->  {(1 + (zext i8 %start to i16))<nuw><nsw>,+,1}<nuw><%loop>
   %idx.inc = add nuw i8 %idx, 1
   %condition = load volatile i1, i1* %c
   br i1 %condition, label %exit, label %loop

diff --git a/test/Analysis/ScalarEvolution/min-max-exprs.ll b/test/Analysis/ScalarEvolution/min-max-exprs.ll
index a4be9c1177311720610d4d12ce34ea35ecba1c94..e8c1e33e095f8499246161393c684135213cdddf 100644 (file)
--- a/test/Analysis/ScalarEvolution/min-max-exprs.ll
+++ b/test/Analysis/ScalarEvolution/min-max-exprs.ll
@@ -33,7 +33,7 @@ bb2:                                              ; preds = %bb1
   %tmp9 = select i1 %tmp4, i64 %tmp5, i64 %tmp6
 ;                  min(N, i+3)
 ; CHECK:           select i1 %tmp4, i64 %tmp5, i64 %tmp6
-; CHECK-NEXT:  --> (-1 + (-1 * ((-1 + (-1 * (sext i32 {3,+,1}<nw><%bb1> to i64))<nsw>) smax (-1 + (-1 * (sext i32 %N to i64))<nsw>)))<nsw>)
+; CHECK-NEXT:  --> (-1 + (-1 * ((-1 + (-1 * (sext i32 {3,+,1}<nuw><%bb1> to i64))<nsw>)<nsw> smax (-1 + (-1 * (sext i32 %N to i64))<nsw>)<nsw>))<nsw>)<nsw>
   %tmp11 = getelementptr inbounds i32, i32* %A, i64 %tmp9
   %tmp12 = load i32, i32* %tmp11, align 4
   %tmp13 = shl nsw i32 %tmp12, 1

diff --git a/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll b/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll
new file mode 100644 (file)
index 0000000..49a4f4f
--- /dev/null
+++ b/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll
@@ -0,0 +1,44 @@
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+!0 = !{i8 0, i8 127}
+
+define void @f0(i8* %len_addr) {
+; CHECK-LABEL: Classifying expressions for: @f0
+ entry:
+  %len = load i8, i8* %len_addr, !range !0
+  %len_norange = load i8, i8* %len_addr
+; CHECK:  %len = load i8, i8* %len_addr, !range !0
+; CHECK-NEXT:  -->  %len U: [0,127) S: [0,127)
+; CHECK:  %len_norange = load i8, i8* %len_addr
+; CHECK-NEXT:  -->  %len_norange U: full-set S: full-set
+
+  %t0 = add i8 %len, 1
+  %t1 = add i8 %len, 2
+; CHECK:  %t0 = add i8 %len, 1
+; CHECK-NEXT:  -->  (1 + %len)<nuw><nsw> U: [1,-128) S: [1,-128)
+; CHECK:  %t1 = add i8 %len, 2
+; CHECK-NEXT:  -->  (2 + %len)<nuw> U: [2,-127) S: [2,-127)
+
+  %t2 = sub i8 %len, 1
+  %t3 = sub i8 %len, 2
+; CHECK:  %t2 = sub i8 %len, 1
+; CHECK-NEXT:  -->  (-1 + %len)<nsw> U: [-1,126) S: [-1,126)
+; CHECK:  %t3 = sub i8 %len, 2
+; CHECK-NEXT:  -->  (-2 + %len)<nsw> U: [-2,125) S: [-2,125)
+
+  %q0 = add i8 %len_norange, 1
+  %q1 = add i8 %len_norange, 2
+; CHECK:  %q0 = add i8 %len_norange, 1
+; CHECK-NEXT:  -->  (1 + %len_norange) U: full-set S: full-set
+; CHECK:  %q1 = add i8 %len_norange, 2
+; CHECK-NEXT:  -->  (2 + %len_norange) U: full-set S: full-set
+
+  %q2 = sub i8 %len_norange, 1
+  %q3 = sub i8 %len_norange, 2
+; CHECK:  %q2 = sub i8 %len_norange, 1
+; CHECK-NEXT:  -->  (-1 + %len_norange) U: full-set S: full-set
+; CHECK:  %q3 = sub i8 %len_norange, 2
+; CHECK-NEXT:  -->  (-2 + %len_norange) U: full-set S: full-set
+
+  ret void
+}

diff --git a/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll b/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll
index 483becc0e7b8a71f8ade8623faeb85486a89e07b..c6d6690e4302a0efe89170fad80941cc6dfbf931 100644 (file)
--- a/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll
+++ b/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll
@@ -28,7 +28,7 @@ exit:
 ; sure they aren't marked as post-inc users.
 ;
 ; CHECK-LABEL: IV Users for loop %test2.loop
-; CHECK: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us)),+,33554432}<%test2.loop> in %f = ashr i32 %sext.us, 24
+; CHECK: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us))<nuw><nsw>,+,33554432}<%test2.loop> in %f = ashr i32 %sext.us, 24
 define i32 @test2() {
 entry:
   br label %test2.loop