From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Sun, 2 Aug 2015 15:28:10 +0000 (+0000)
Subject: Fix invalid shufflevector operands
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2a3c90446125f7ce6223eaadb424a6e59e90015c;p=clang

Fix invalid shufflevector operands

This patch fixes bug 23800 ( https://llvm.org/bugs/show_bug.cgi?id=23800#c2 ). There existed a case where the index operand from extractelement was directly used to create a shufflevector mask. Since the index can be of any integral type but the mask must only contain 32 bit integers a 64 bit index operand led to an assertion error later on.

Committed on behalf of mpflanzer (Moritz Pflanzer)

Differential Revision: http://reviews.llvm.org/D10838

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@243851 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index f3e4836213..195c7a4678 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -1162,6 +1162,16 @@ static llvm::Constant *getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
   return llvm::ConstantInt::get(I32Ty, Off+MV);
 }
 
+static llvm::Constant *getAsInt32(llvm::ConstantInt *C, llvm::Type *I32Ty) {
+  if (C->getBitWidth() != 32) {
+      assert(llvm::ConstantInt::isValueValidForType(I32Ty,
+                                                    C->getZExtValue()) &&
+             "Index operand too large for shufflevector mask!");
+      return llvm::ConstantInt::get(I32Ty, C->getZExtValue());
+  }
+  return C;
+}
+
 Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
   bool Ignore = TestAndClearIgnoreResultAssign();
   (void)Ignore;
@@ -1212,7 +1222,8 @@ Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
           Value *LHS = nullptr, *RHS = nullptr;
           if (CurIdx == 0) {
             // insert into undef -> shuffle (src, undef)
-            Args.push_back(C);
+            // shufflemask must use an i32
+            Args.push_back(getAsInt32(C, CGF.Int32Ty));
             Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
 
             LHS = EI->getVectorOperand();
diff --git a/test/CodeGenOpenCL/vector_shufflevector_valid.cl b/test/CodeGenOpenCL/vector_shufflevector_valid.cl
new file mode 100644
index 0000000000..0953c66f58
--- /dev/null
+++ b/test/CodeGenOpenCL/vector_shufflevector_valid.cl
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -emit-llvm -O0 %s -o - | FileCheck %s
+
+// The shuffle vector mask must always be of i32 vector type
+// See http://reviews.llvm.org/D10838 and https://llvm.org/bugs/show_bug.cgi?id=23800#c2
+// for more information about a bug where a 64 bit index operand causes the generation
+// of an invalid mask
+
+typedef unsigned int uint2 __attribute((ext_vector_type(2)));
+
+void vector_shufflevector_valid(void) {
+    //CHECK: {{%.*}} = shufflevector <2 x i32> {{%.*}}, <2 x i32> undef, <2 x i32> <i32 0, i32 undef>
+    (uint2)(((uint2)(0)).s0, 0);
+}