[llvm-commits] [llvm] r61613 - in /llvm/trunk: lib/CodeGen/SelectionDAG/DAGCombiner.cpp test/CodeGen/X86/pr3250.ll

[Dan Gohman]

Author: djg
Date: Sat Jan  3 13:22:06 2009
New Revision: 61613

URL: http://llvm.org/viewvc/llvm-project?rev=61613&view=rev
Log:
Fix a DAGCombiner abort on an invalid shift count constant. This fixes PR3250.

Added:
    llvm/trunk/test/CodeGen/X86/pr3250.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=61613&r1=61612&r2=61613&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Sat Jan  3 13:22:06 2009
@@ -3277,6 +3277,8 @@
     if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) {
       // See if we can recursively simplify the LHS.
       unsigned Amt = RHSC->getZExtValue();
+      // Watch out for shift count overflow though.
+      if (Amt >= Mask.getBitWidth()) break;
       APInt NewMask = Mask << Amt;
       SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask);
       if (SimplifyLHS.getNode()) {

Added: llvm/trunk/test/CodeGen/X86/pr3250.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr3250.ll?rev=61613&view=auto

==============================================================================
--- llvm/trunk/test/CodeGen/X86/pr3250.ll (added)
+++ llvm/trunk/test/CodeGen/X86/pr3250.ll Sat Jan  3 13:22:06 2009
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | llc -march=x86
+; PR3250
+
+declare i32 @safe_sub_func_short_u_u(i16 signext, i16 signext) nounwind
+
+define i32 @func_106(i32 %p_107) nounwind {
+entry:
+        %0 = tail call i32 (...)* @safe_div_(i32 %p_107, i32 1) nounwind       
+        ; <i32> [#uses=1]
+        %1 = lshr i32 %0, -9            ; <i32> [#uses=1]
+        %2 = trunc i32 %1 to i16                ; <i16> [#uses=1]
+        %3 = tail call i32 @safe_sub_func_short_u_u(i16 signext 1, i16 signext
+%2) nounwind             ; <i32> [#uses=0]
+        ret i32 undef
+}
+
+declare i32 @safe_div_(...)