IntrWriteArgMem implies nocapture, but this wasn't

taken advantage of anywhere.  Change the definition
of IntrWriteArgMem to no longer imply nocapture, and
explicitly add nocapture attributes everywhere (well,
not quite everywhere, because some of these intrinsics
did capture their arguments!).  Also, make clear that
the lack of other side-effects does not exclude doing
volatile loads or stores - the atomic intrinsics do
these, yet they are all marked IntrWriteArgMem (this
change is safe because nothing exploited it).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64539 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 17 deletions

diff --git a/include/llvm/Intrinsics.td b/include/llvm/Intrinsics.td
index 4ecc1a7052..df15a66809 100644
--- a/include/llvm/Intrinsics.td
+++ b/include/llvm/Intrinsics.td
@@ -38,9 +38,8 @@ def IntrReadArgMem : IntrinsicProperty;
 def IntrReadMem : IntrinsicProperty;
 
 // IntrWriteArgMem - This intrinsic reads and writes only from memory that one
-// of its arguments points to, but may access an unspecified amount.  It has no
-// other side effects.  This may only be used if the intrinsic doesn't "capture"
-// the argument pointer (e.g. storing it someplace).
+// of its arguments points to, but may access an unspecified amount.  The reads
+// and writes may be volatile, but except for this it has no other side effects.
 def IntrWriteArgMem : IntrinsicProperty;
 
 // IntrWriteMem - This intrinsic may read or modify unspecified memory or has 
@@ -173,7 +172,7 @@ def int_gcread  : Intrinsic<[llvm_ptr_ty],
                             [IntrReadArgMem]>;
 def int_gcwrite : Intrinsic<[llvm_void_ty],
                             [llvm_ptr_ty, llvm_ptr_ty, llvm_ptrptr_ty],
-                            [IntrWriteArgMem]>;
+                            [IntrWriteArgMem, NoCapture<1>, NoCapture<2>]>;
 
 //===--------------------- Code Generator Intrinsics ----------------------===//
 //  
@@ -192,7 +191,7 @@ def int_stackrestore  : Intrinsic<[llvm_void_ty], [llvm_ptr_ty]>,
 // with respect to nearby accesses to the same memory.
 def int_prefetch      : Intrinsic<[llvm_void_ty],
                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
-                                  [IntrWriteArgMem]>;
+                                  [IntrWriteArgMem, NoCapture<0>]>;
 def int_pcmarker      : Intrinsic<[llvm_void_ty], [llvm_i32_ty]>;
 
 def int_readcyclecounter : Intrinsic<[llvm_i64_ty]>;
@@ -340,62 +339,62 @@ def int_memory_barrier : Intrinsic<[llvm_void_ty],
 def int_atomic_cmp_swap : Intrinsic<[llvm_anyint_ty],
                                     [LLVMAnyPointerType<LLVMMatchType<0>>,
                                      LLVMMatchType<0>, LLVMMatchType<0>],
-                                    [IntrWriteArgMem]>,
+                                    [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_val_compare_and_swap">;
 def int_atomic_load_add : Intrinsic<[llvm_anyint_ty],
                                     [LLVMAnyPointerType<LLVMMatchType<0>>,
                                      LLVMMatchType<0>],
-                                    [IntrWriteArgMem]>,
+                                    [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_add">;
 def int_atomic_swap     : Intrinsic<[llvm_anyint_ty],
                                     [LLVMAnyPointerType<LLVMMatchType<0>>,
                                      LLVMMatchType<0>],
-                                    [IntrWriteArgMem]>,
+                                    [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_lock_test_and_set">;
 def int_atomic_load_sub : Intrinsic<[llvm_anyint_ty],
                                     [LLVMAnyPointerType<LLVMMatchType<0>>,
                                      LLVMMatchType<0>],
-                                    [IntrWriteArgMem]>,
+                                    [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_sub">;
 def int_atomic_load_and : Intrinsic<[llvm_anyint_ty],
                                     [LLVMAnyPointerType<LLVMMatchType<0>>,
                                      LLVMMatchType<0>],
-                                    [IntrWriteArgMem]>,
+                                    [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_and">;
 def int_atomic_load_or   : Intrinsic<[llvm_anyint_ty],
                                      [LLVMAnyPointerType<LLVMMatchType<0>>,
                                       LLVMMatchType<0>],
-                                     [IntrWriteArgMem]>,
+                                     [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_or">;
 def int_atomic_load_xor : Intrinsic<[llvm_anyint_ty],
                                     [LLVMAnyPointerType<LLVMMatchType<0>>,
                                      LLVMMatchType<0>],
-                                    [IntrWriteArgMem]>,
+                                    [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_xor">;
 def int_atomic_load_nand : Intrinsic<[llvm_anyint_ty],
                                      [LLVMAnyPointerType<LLVMMatchType<0>>,
                                       LLVMMatchType<0>],
-                                     [IntrWriteArgMem]>,
+                                     [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_nand">;
 def int_atomic_load_min  : Intrinsic<[llvm_anyint_ty],
                                      [LLVMAnyPointerType<LLVMMatchType<0>>,
                                       LLVMMatchType<0>],
-                                     [IntrWriteArgMem]>,
+                                     [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_min">;
 def int_atomic_load_max  : Intrinsic<[llvm_anyint_ty],
                                      [LLVMAnyPointerType<LLVMMatchType<0>>,
                                       LLVMMatchType<0>],
-                                     [IntrWriteArgMem]>,
+                                     [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_max">;
 def int_atomic_load_umin : Intrinsic<[llvm_anyint_ty],
                                      [LLVMAnyPointerType<LLVMMatchType<0>>,
                                       LLVMMatchType<0>],
-                                     [IntrWriteArgMem]>,
+                                     [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_umin">;
 def int_atomic_load_umax : Intrinsic<[llvm_anyint_ty],
                                      [LLVMAnyPointerType<LLVMMatchType<0>>,
                                       LLVMMatchType<0>],
-                                     [IntrWriteArgMem]>,
+                                     [IntrWriteArgMem, NoCapture<0>]>,
                            GCCBuiltin<"__sync_fetch_and_umax">;
                                   
 //===-------------------------- Other Intrinsics --------------------------===//