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Model stacksave and stackrestore as both writing memory, since we 

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

llvm-svn: 43442
This commit is contained in:
Chris Lattner 2007-10-29 05:47:52 +00:00
parent b104d31bd9
commit c541c3ee15
2 changed files with 51 additions and 1 deletions
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5
llvm/include/llvm/Intrinsics.td
View File

@ -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">;

47
llvm/test/Transforms/InstCombine/2007-10-28-stacksave.ll Normal file
View File

@ -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*)