[llvm-commits] [llvm] r52702 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2008-06-24-StackRestore.ll

[Chris Lattner]

Author: lattner
Date: Wed Jun 25 00:59:28 2008
New Revision: 52702

URL: http://llvm.org/viewvc/llvm-project?rev=52702&view=rev
Log:
Fix PR2488, a case where we deleted stack restores too aggressively.

Added:
    llvm/trunk/test/Transforms/InstCombine/2008-06-24-StackRestore.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=52702&r1=52701&r2=52702&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Wed Jun 25 00:59:28 2008
@@ -8697,13 +8697,18 @@
         CannotRemove = true;
         break;
       }
-      if (isa<CallInst>(BI)) {
-        if (!isa<IntrinsicInst>(BI)) {
+      if (CallInst *BCI = dyn_cast<CallInst>(BI)) {
+        if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) {
+          // If there is a stackrestore below this one, remove this one.
+          if (II->getIntrinsicID() == Intrinsic::stackrestore)
+            return EraseInstFromFunction(CI);
+          // Otherwise, ignore the intrinsic.
+        } else {
+          // If we found a non-intrinsic call, we can't remove the stack
+          // restore.
           CannotRemove = true;
           break;
         }
-        // If there is a stackrestore below this one, remove this one.
-        return EraseInstFromFunction(CI);
       }
     }
     

Added: llvm/trunk/test/Transforms/InstCombine/2008-06-24-StackRestore.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2008-06-24-StackRestore.ll?rev=52702&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2008-06-24-StackRestore.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2008-06-24-StackRestore.ll Wed Jun 25 00:59:28 2008
@@ -0,0 +1,39 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {call.*llvm.stackrestore}
+; PR2488
+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-f80:32:32"
+target triple = "i386-pc-linux-gnu"
+ at p = weak global i8* null		; <i8**> [#uses=2]
+
+define i32 @main() nounwind  {
+entry:
+	%tmp248 = call i8* @llvm.stacksave( )		; <i8*> [#uses=1]
+	%tmp2752 = alloca i32		; <i32*> [#uses=2]
+	%tmpcast53 = bitcast i32* %tmp2752 to i8*		; <i8*> [#uses=1]
+	store i32 2, i32* %tmp2752, align 4
+	volatile store i8* %tmpcast53, i8** @p, align 4
+	br label %bb44
+
+bb:		; preds = %bb44
+	ret i32 0
+
+bb44:		; preds = %bb44, %entry
+	%indvar = phi i32 [ 0, %entry ], [ %tmp3857, %bb44 ]		; <i32> [#uses=1]
+	%tmp249 = phi i8* [ %tmp248, %entry ], [ %tmp2, %bb44 ]		; <i8*> [#uses=1]
+	%tmp3857 = add i32 %indvar, 1		; <i32> [#uses=3]
+	call void @llvm.stackrestore( i8* %tmp249 )
+	%tmp2 = call i8* @llvm.stacksave( )		; <i8*> [#uses=1]
+	%tmp4 = srem i32 %tmp3857, 1000		; <i32> [#uses=2]
+	%tmp5 = add i32 %tmp4, 1		; <i32> [#uses=1]
+	%tmp27 = alloca i32, i32 %tmp5		; <i32*> [#uses=3]
+	%tmpcast = bitcast i32* %tmp27 to i8*		; <i8*> [#uses=1]
+	store i32 1, i32* %tmp27, align 4
+	%tmp34 = getelementptr i32* %tmp27, i32 %tmp4		; <i32*> [#uses=1]
+	store i32 2, i32* %tmp34, align 4
+	volatile store i8* %tmpcast, i8** @p, align 4
+	%exitcond = icmp eq i32 %tmp3857, 999999		; <i1> [#uses=1]
+	br i1 %exitcond, label %bb, label %bb44
+}
+
+declare i8* @llvm.stacksave() nounwind 
+
+declare void @llvm.stackrestore(i8*) nounwind