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Avoid aborting on invalid shift counts.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47612 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2008-02-26 18:50:50 +00:00
parent 814ebd77b0
commit d4cf992230
2 changed files with 48 additions and 4 deletions
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22
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View File

@ -1241,13 +1241,19 @@ void SelectionDAG::ComputeMaskedBits(SDOperand Op, const APInt &Mask,
case ISD::SHL:
// (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
ComputeMaskedBits(Op.getOperand(0), Mask.lshr(SA->getValue()),
unsigned ShAmt = SA->getValue();
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
return;
ComputeMaskedBits(Op.getOperand(0), Mask.lshr(ShAmt),
KnownZero, KnownOne, Depth+1);
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero <<= SA->getValue();
KnownOne <<= SA->getValue();
KnownZero <<= ShAmt;
KnownOne <<= ShAmt;
// low bits known zero.
KnownZero |= APInt::getLowBitsSet(BitWidth, SA->getValue());
KnownZero |= APInt::getLowBitsSet(BitWidth, ShAmt);
}
return;
case ISD::SRL:
@ -1255,6 +1261,10 @@ void SelectionDAG::ComputeMaskedBits(SDOperand Op, const APInt &Mask,
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
unsigned ShAmt = SA->getValue();
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
return;
ComputeMaskedBits(Op.getOperand(0), (Mask << ShAmt),
KnownZero, KnownOne, Depth+1);
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
@ -1269,6 +1279,10 @@ void SelectionDAG::ComputeMaskedBits(SDOperand Op, const APInt &Mask,
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
unsigned ShAmt = SA->getValue();
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
return;
APInt InDemandedMask = (Mask << ShAmt);
// If any of the demanded bits are produced by the sign extension, we also
// demand the input sign bit.

30
test/CodeGen/X86/invalid-shift-immediate.ll Normal file
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@ -0,0 +1,30 @@
; RUN: llvm-as < %s | llc -march=x86
; PR2098
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 = "i386-apple-darwin8"
define void @foo(i32 %x) {
entry:
%x_addr = alloca i32 ; <i32*> [#uses=2]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
store i32 %x, i32* %x_addr
%tmp = load i32* %x_addr, align 4 ; <i32> [#uses=1]
%tmp1 = ashr i32 %tmp, -2 ; <i32> [#uses=1]
%tmp2 = and i32 %tmp1, 1 ; <i32> [#uses=1]
%tmp23 = trunc i32 %tmp2 to i8 ; <i8> [#uses=1]
%toBool = icmp ne i8 %tmp23, 0 ; <i1> [#uses=1]
br i1 %toBool, label %bb, label %bb5
bb: ; preds = %entry
%tmp4 = call i32 (...)* @bar( ) nounwind ; <i32> [#uses=0]
br label %bb5
bb5: ; preds = %bb, %entry
br label %return
return: ; preds = %bb5
ret void
}
declare i32 @bar(...)