Model stacksave and stackrestore as both writing memory, since we

don't model their dependences on allocas correctly.  This fixes
PR1745.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43442 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Intrinsics.td b/include/llvm/Intrinsics.td
index d205d98eb99b826a5317c2bd93dc723ea9b3b427..9819f38952c2f53e510c2e7f5589ecd3ece1bf2b 100644 (file)
--- a/include/llvm/Intrinsics.td
+++ b/include/llvm/Intrinsics.td
@@ -149,7 +149,10 @@ def int_gcwrite : Intrinsic<[llvm_void_ty, llvm_ptr_ty, llvm_ptr_ty,
 //  
 def int_returnaddress : Intrinsic<[llvm_ptr_ty, llvm_i32_ty], [IntrNoMem]>;
 def int_frameaddress  : Intrinsic<[llvm_ptr_ty, llvm_i32_ty], [IntrNoMem]>;
-def int_stacksave     : Intrinsic<[llvm_ptr_ty], [IntrReadMem]>,
+
+// Note: we treat stacksave/stackrestore as writemem because we don't otherwise
+// model their dependencies on allocas.
+def int_stacksave     : Intrinsic<[llvm_ptr_ty]>,
                         GCCBuiltin<"__builtin_stack_save">;
 def int_stackrestore  : Intrinsic<[llvm_void_ty, llvm_ptr_ty]>,
                         GCCBuiltin<"__builtin_stack_restore">;

diff --git a/test/Transforms/InstCombine/2007-10-28-stacksave.ll b/test/Transforms/InstCombine/2007-10-28-stacksave.ll
new file mode 100644 (file)
index 0000000..5f884d4
--- /dev/null
+++ b/test/Transforms/InstCombine/2007-10-28-stacksave.ll
@@ -0,0 +1,47 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {call.*stacksave}
+; PR1745
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i686-apple-darwin8"
+@p = weak global i8* null              ; <i8**> [#uses=1]
+
+define i32 @main() {
+entry:
+       %"alloca point" = bitcast i32 0 to i32          ; <i32> [#uses=0]
+       br label %lab
+
+lab:           ; preds = %cleanup31, %entry
+       %n.0 = phi i32 [ 0, %entry ], [ %tmp25, %cleanup31 ]            ; <i32> [#uses=2]
+       %tmp2 = call i8* @llvm.stacksave( )             ; <i8*> [#uses=2]
+       %tmp4 = srem i32 %n.0, 47               ; <i32> [#uses=1]
+       %tmp5 = add i32 %tmp4, 1                ; <i32> [#uses=5]
+       %tmp7 = sub i32 %tmp5, 1                ; <i32> [#uses=0]
+       %tmp89 = zext i32 %tmp5 to i64          ; <i64> [#uses=1]
+       %tmp10 = mul i64 %tmp89, 32             ; <i64> [#uses=0]
+       %tmp12 = mul i32 %tmp5, 4               ; <i32> [#uses=0]
+       %tmp1314 = zext i32 %tmp5 to i64                ; <i64> [#uses=1]
+       %tmp15 = mul i64 %tmp1314, 32           ; <i64> [#uses=0]
+       %tmp17 = mul i32 %tmp5, 4               ; <i32> [#uses=1]
+       %tmp18 = alloca i8, i32 %tmp17          ; <i8*> [#uses=1]
+       %tmp1819 = bitcast i8* %tmp18 to i32*           ; <i32*> [#uses=2]
+       %tmp21 = getelementptr i32* %tmp1819, i32 0             ; <i32*> [#uses=1]
+       store i32 1, i32* %tmp21, align 4
+       %tmp2223 = bitcast i32* %tmp1819 to i8*         ; <i8*> [#uses=1]
+       volatile store i8* %tmp2223, i8** @p, align 4
+       %tmp25 = add i32 %n.0, 1                ; <i32> [#uses=2]
+       %tmp27 = icmp sle i32 %tmp25, 999999            ; <i1> [#uses=1]
+       %tmp2728 = zext i1 %tmp27 to i8         ; <i8> [#uses=1]
+       %toBool = icmp ne i8 %tmp2728, 0                ; <i1> [#uses=1]
+       br i1 %toBool, label %cleanup31, label %cond_next
+
+cond_next:             ; preds = %lab
+       call void @llvm.stackrestore( i8* %tmp2 )
+       ret i32 0
+
+cleanup31:             ; preds = %lab
+       call void @llvm.stackrestore( i8* %tmp2 )
+       br label %lab
+}
+
+declare i8* @llvm.stacksave()
+
+declare void @llvm.stackrestore(i8*)