Implement builtins for safe division: safe.sdiv.iN, safe.udiv.iN, safe.srem.iN,

safe.urem.iN (iN = i8, i16, i32, or i64).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206732 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 29 insertions, 0 deletions

diff --git a/include/llvm/IR/Intrinsics.td b/include/llvm/IR/Intrinsics.td
index 6a48f17393..c65b86f5b7 100644
--- a/include/llvm/IR/Intrinsics.td
+++ b/include/llvm/IR/Intrinsics.td
@@ -444,6 +444,19 @@ def int_umul_with_overflow : Intrinsic<[llvm_anyint_ty, llvm_i1_ty],
                                        [LLVMMatchType<0>, LLVMMatchType<0>],
                                        [IntrNoMem]>;
 
+def int_safe_udiv : Intrinsic<[llvm_anyint_ty, llvm_i1_ty],
+                              [LLVMMatchType<0>, LLVMMatchType<0>],
+                              [IntrNoMem]>;
+def int_safe_urem : Intrinsic<[llvm_anyint_ty, llvm_i1_ty],
+                              [LLVMMatchType<0>, LLVMMatchType<0>],
+                              [IntrNoMem]>;
+def int_safe_sdiv : Intrinsic<[llvm_anyint_ty, llvm_i1_ty],
+                              [LLVMMatchType<0>, LLVMMatchType<0>],
+                              [IntrNoMem]>;
+def int_safe_srem : Intrinsic<[llvm_anyint_ty, llvm_i1_ty],
+                              [LLVMMatchType<0>, LLVMMatchType<0>],
+                              [IntrNoMem]>;
+
 //===------------------------- Memory Use Markers -------------------------===//
 //
 def int_lifetime_start  : Intrinsic<[],
diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index 5afcd80a28..2e4956f16d 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -218,6 +218,10 @@ public:
   /// Return true if pow2 div is cheaper than a chain of srl/add/sra.
   bool isPow2DivCheap() const { return Pow2DivIsCheap; }
 
+  /// Return true if Div never traps, returns 0 when div by 0 and return TMin,
+  /// when sdiv TMin by -1.
+  bool isDivWellDefined() const { return DivIsWellDefined; }
+
   /// Return true if Flow Control is an expensive operation that should be
   /// avoided.
   bool isJumpExpensive() const { return JumpIsExpensive; }
@@ -1026,6 +1030,13 @@ protected:
   /// signed divide by power of two, and let the target handle it.
   void setPow2DivIsCheap(bool isCheap = true) { Pow2DivIsCheap = isCheap; }
 
+  /// Tells the code-generator that it is safe to execute sdiv/udiv/srem/urem
+  /// even when RHS is 0. It is also safe to execute sdiv/srem when LHS is
+  /// SignedMinValue and RHS is -1.
+  void setDivIsWellDefined (bool isWellDefined = true) {
+    DivIsWellDefined = isWellDefined;
+  }
+
   /// Add the specified register class as an available regclass for the
   /// specified value type. This indicates the selector can handle values of
   /// that class natively.
@@ -1441,6 +1452,11 @@ private:
   /// signed divide by power of two, and let the target handle it.
   bool Pow2DivIsCheap;
 
+  /// Tells the code-generator that it is safe to execute sdiv/udiv/srem/urem
+  /// even when RHS is 0. It is also safe to execute sdiv/srem when LHS is
+  /// SignedMinValue and RHS is -1.
+  bool DivIsWellDefined;
+
   /// Tells the code generator that it shouldn't generate extra flow control
   /// instructions and should attempt to combine flow control instructions via
   /// predication.