From: Tim Northover <tnorthover@apple.com>
Date: Thu, 4 Aug 2016 20:54:05 +0000 (+0000)
Subject: GlobalISel: refuse to halve size  of 1-byte & odd-sized LLTs.
X-Git-Tag: llvmorg-4.0.0-rc1~13293
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=404f1b7db566651464efbc6aa2a195bc444e3ba2;p=platform%2Fupstream%2Fllvm.git

GlobalISel: refuse to halve size  of 1-byte & odd-sized LLTs.

llvm-svn: 277768
---

diff --git a/llvm/include/llvm/CodeGen/LowLevelType.h b/llvm/include/llvm/CodeGen/LowLevelType.h
index 4d21a15..34210f2 100644
--- a/llvm/include/llvm/CodeGen/LowLevelType.h
+++ b/llvm/include/llvm/CodeGen/LowLevelType.h
@@ -131,7 +131,8 @@ public:
   /// size of the scalar type involved. For example `s32` will become `s16`,
   /// `<2 x s32>` will become `<2 x s16>`.
   LLT halfScalarSize() const {
-    assert(isSized() && "cannot change size of this type");
+    assert(isSized() && getScalarSizeInBits() > 1 &&
+           getScalarSizeInBits() % 2 == 0 && "cannot half size of this type");
     return LLT{Kind, NumElements, SizeOrAddrSpace / 2};
   }
 
diff --git a/llvm/unittests/CodeGen/LowLevelTypeTest.cpp b/llvm/unittests/CodeGen/LowLevelTypeTest.cpp
index 79e66ec..04a43ea 100644
--- a/llvm/unittests/CodeGen/LowLevelTypeTest.cpp
+++ b/llvm/unittests/CodeGen/LowLevelTypeTest.cpp
@@ -34,7 +34,7 @@ TEST(LowLevelTypeTest, Scalar) {
 
   for (unsigned S : {1U, 17U, 32U, 64U, 0xfffffU}) {
     const LLT Ty = LLT::scalar(S);
-    const LLT HalfTy = Ty.halfScalarSize();
+    const LLT HalfTy = (S % 2) == 0 ? Ty.halfScalarSize() : Ty;
     const LLT DoubleTy = Ty.doubleScalarSize();
 
     // Test kind.
@@ -51,13 +51,14 @@ TEST(LowLevelTypeTest, Scalar) {
     EXPECT_EQ(S, Ty.getSizeInBits());
     EXPECT_EQ(S, Ty.getScalarSizeInBits());
 
-    // Is it OK to half an odd-sized scalar? It currently is.
-    EXPECT_EQ(S/2, HalfTy.getSizeInBits());
-    EXPECT_EQ(S/2, HalfTy.getScalarSizeInBits());
-
     EXPECT_EQ(S*2, DoubleTy.getSizeInBits());
     EXPECT_EQ(S*2, DoubleTy.getScalarSizeInBits());
 
+    if ((S % 2) == 0) {
+      EXPECT_EQ(S/2, HalfTy.getSizeInBits());
+      EXPECT_EQ(S/2, HalfTy.getScalarSizeInBits());
+    }
+
     // Test equality operators.
     EXPECT_TRUE(Ty == Ty);
     EXPECT_FALSE(Ty != Ty);
@@ -87,7 +88,7 @@ TEST(LowLevelTypeTest, Vector) {
       // Test getElementType().
       EXPECT_EQ(STy, VTy.getElementType());
 
-      const LLT HalfSzTy = VTy.halfScalarSize();
+      const LLT HalfSzTy = ((S % 2) == 0) ? VTy.halfScalarSize() : VTy;
       const LLT DoubleSzTy = VTy.doubleScalarSize();
 
       // halfElements requires an even number of elements.
@@ -123,9 +124,11 @@ TEST(LowLevelTypeTest, Vector) {
       EXPECT_EQ(S, VTy.getScalarSizeInBits());
       EXPECT_EQ(Elts, VTy.getNumElements());
 
-      EXPECT_EQ((S / 2) * Elts, HalfSzTy.getSizeInBits());
-      EXPECT_EQ(S / 2, HalfSzTy.getScalarSizeInBits());
-      EXPECT_EQ(Elts, HalfSzTy.getNumElements());
+      if ((S % 2) == 0) {
+        EXPECT_EQ((S / 2) * Elts, HalfSzTy.getSizeInBits());
+        EXPECT_EQ(S / 2, HalfSzTy.getScalarSizeInBits());
+        EXPECT_EQ(Elts, HalfSzTy.getNumElements());
+      }
 
       EXPECT_EQ((S * 2) * Elts, DoubleSzTy.getSizeInBits());
       EXPECT_EQ(S * 2, DoubleSzTy.getScalarSizeInBits());