From: David Majnemer <david.majnemer@gmail.com>
Date: Thu, 12 Feb 2015 23:26:26 +0000 (+0000)
Subject: X86: Don't crash if we can't decode the pshufb mask
X-Git-Tag: llvmorg-3.7.0-rc1~12313
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a12fcb790fb3694c6fcdf14047be72283ae4a0ee;p=platform%2Fupstream%2Fllvm.git

X86: Don't crash if we can't decode the pshufb mask

Constant pool entries are uniqued by their contents regardless of their
type.  This means that a pshufb can have a shuffle mask which isn't a
simple array of bytes.

The code path which attempts to decode the mask didn't check for
failure, causing PR22559.

llvm-svn: 228979
---

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index c11c8e3..3c2e27a 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -5480,6 +5480,8 @@ static bool getTargetShuffleMask(SDNode *N, MVT VT,
 
     if (auto *C = dyn_cast<Constant>(MaskCP->getConstVal())) {
       DecodePSHUFBMask(C, Mask);
+      if (Mask.empty())
+        return false;
       break;
     }
 
diff --git a/llvm/test/CodeGen/X86/pshufb-mask-comments.ll b/llvm/test/CodeGen/X86/pshufb-mask-comments.ll
index 303c4a6..ca5a02c 100644
--- a/llvm/test/CodeGen/X86/pshufb-mask-comments.ll
+++ b/llvm/test/CodeGen/X86/pshufb-mask-comments.ll
@@ -37,4 +37,16 @@ define <16 x i8> @test4(<2 x i64>* %V) {
   ret <16 x i8> %1
 }
 
+define <16 x i8> @test5() {
+; CHECK-LABEL: test5
+; CHECK: pshufb {{.*}}
+  store <2 x i64> <i64 1, i64 0>, <2 x i64>* undef, align 16
+  %l = load <2 x i64>* undef, align 16
+  %shuffle = shufflevector <2 x i64> %l, <2 x i64> undef, <2 x i32> zeroinitializer
+  store <2 x i64> %shuffle, <2 x i64>* undef, align 16
+  %1 = load <16 x i8>* undef, align 16
+  %2 = call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> undef, <16 x i8> %1)
+  ret <16 x i8> %2
+}
+
 declare <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8>, <16 x i8>) nounwind readnone