Add tests

Author: mrdaybird

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -13003,7 +13003,7 @@ ScalarEvolution::howManyLessThans(const SCEV *LHS, const SCEV *RHS,
   const SCEV *End = nullptr, *BECount = nullptr,
              *BECountIfBackedgeTaken = nullptr;
   if (!isLoopInvariant(RHS, L)) {
-    if (auto RHSAddRec = dyn_cast<SCEVAddRecExpr>(RHS)) {
+    if (const auto *RHSAddRec = dyn_cast<SCEVAddRecExpr>(RHS)) {
       /*
         The structure of loop we are trying to calculate backedge-count of:
         left = left_start
@@ -13026,7 +13026,7 @@ ScalarEvolution::howManyLessThans(const SCEV *LHS, const SCEV *RHS,
       // check if RHSStride<0 and Stride-RHSStride will not overflow
       // FIXME: Can RHSStride be positive?
       if (isKnownNegative(RHSStride) &&
-          willNotOverflow(llvm::Instruction::Sub, true, Stride, RHSStride)) {
+          willNotOverflow(Instruction::Sub, /*Signed=*/true, Stride, RHSStride)) {
 
         const SCEV *Denominator = getMinusSCEV(Stride, RHSStride);
         if (isKnownPositive(Denominator)) {

llvm/test/Analysis/ScalarEvolution/pr92560.ll

@@ -0,0 +1,69 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -disable-output "-passes=print<scalar-evolution>" < %s 2>&1 | FileCheck %s
+
+define dso_local void @simple(i32 noundef %n) local_unnamed_addr {
+; CHECK-LABEL: 'simple'
+; CHECK-NEXT:  Classifying expressions for: @simple
+; CHECK-NEXT:    %right.06 = phi i32 [ %dec, %while.body ], [ %n, %entry ]
+; CHECK-NEXT:    --> {%n,+,-4}<nsw><%while.body> U: full-set S: full-set Exits: ((-4 * (((-4 + (-1 * (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))<nuw><nsw> + (4 smax (-4 + %n))) /u 8) + (1 umin (-4 + (4 smax (-4 + %n)))<nsw>)))<nsw> + %n) LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:    %left.05 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
+; CHECK-NEXT:    --> {0,+,4}<nuw><nsw><%while.body> U: [0,2147483641) S: [0,2147483641) Exits: (4 * (((-4 + (-1 * (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))<nuw><nsw> + (4 smax (-4 + %n))) /u 8) + (1 umin (-4 + (4 smax (-4 + %n)))<nsw>)))<nuw> LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:    %inc = add nuw nsw i32 %left.05, 4
+; CHECK-NEXT:    --> {4,+,4}<nuw><nsw><%while.body> U: [4,2147483645) S: [4,2147483645) Exits: (4 + (4 * (((-4 + (-1 * (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))<nuw><nsw> + (4 smax (-4 + %n))) /u 8) + (1 umin (-4 + (4 smax (-4 + %n)))<nsw>)))<nuw>)<nuw> LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:    %dec = add nsw i32 %right.06, -4
+; CHECK-NEXT:    --> {(-4 + %n),+,-4}<nsw><%while.body> U: full-set S: full-set Exits: (-4 + (-4 * (((-4 + (-1 * (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))<nuw><nsw> + (4 smax (-4 + %n))) /u 8) + (1 umin (-4 + (4 smax (-4 + %n)))<nsw>)))<nsw> + %n) LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:  Determining loop execution counts for: @simple
+; CHECK-NEXT:  Loop %while.body: backedge-taken count is (((-4 + (-1 * (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))<nuw><nsw> + (4 smax (-4 + %n))) /u 8) + (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))
+; CHECK-NEXT:  Loop %while.body: constant max backedge-taken count is i32 536870910
+; CHECK-NEXT:  Loop %while.body: symbolic max backedge-taken count is (((-4 + (-1 * (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))<nuw><nsw> + (4 smax (-4 + %n))) /u 8) + (1 umin (-4 + (4 smax (-4 + %n)))<nsw>))
+; CHECK-NEXT:  Loop %while.body: Trip multiple is 1
+;
+entry:
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %while.body, label %while.end
+
+while.body:
+  %right.06 = phi i32 [ %dec, %while.body ], [ %n, %entry ]
+  %left.05 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
+  %inc = add nuw nsw i32 %left.05, 4
+  %dec = add nsw i32 %right.06, -4
+  %cmp = icmp slt i32 %inc, %dec
+  br i1 %cmp, label %while.body, label %while.end
+
+while.end:
+  ret void
+}
+
+define dso_local void @overflow(i32 noundef %n) local_unnamed_addr {
+; CHECK-LABEL: 'overflow'
+; CHECK-NEXT:  Classifying expressions for: @overflow
+; CHECK-NEXT:    %right.06 = phi i32 [ %dec, %while.body ], [ %n, %entry ]
+; CHECK-NEXT:    --> {%n,+,-1}<nsw><%while.body> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:    %left.05 = phi i32 [ %inc, %while.body ], [ 2147483647, %entry ]
+; CHECK-NEXT:    --> {2147483647,+,2147483647}<nuw><nsw><%while.body> U: [2147483647,-2147483648) S: [2147483647,-2147483648) Exits: <<Unknown>> LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:    %inc = add nuw nsw i32 %left.05, 2147483647
+; CHECK-NEXT:    --> {-2,+,2147483647}<nuw><nsw><%while.body> U: [-2,-1) S: [-2,0) Exits: <<Unknown>> LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:    %dec = add nsw i32 %right.06, -1
+; CHECK-NEXT:    --> {(-1 + %n),+,-1}<nsw><%while.body> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %while.body: Computable }
+; CHECK-NEXT:  Determining loop execution counts for: @overflow
+; CHECK-NEXT:  Loop %while.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %while.body: constant max backedge-taken count is i32 1
+; CHECK-NEXT:  Loop %while.body: symbolic max backedge-taken count is i32 1
+;
+entry:
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %while.body, label %while.end
+
+while.body:
+  %right.06 = phi i32 [ %dec, %while.body ], [ %n, %entry ]
+  %left.05 = phi i32 [ %inc, %while.body ], [ 2147483647, %entry ]
+  %inc = add nuw nsw i32 %left.05, 2147483647
+  %dec = add nsw i32 %right.06, -1
+  %cmp = icmp slt i32 %inc, %dec
+  br i1 %cmp, label %while.body, label %while.end
+
+while.end:
+  ret void
+}
+
+