Fix 9267; Add vector zext support.

The DAGCombiner folds the zext into complex load instructions. This patch
prevents this optimization on vectors since none of the supported targets
knows how to perform load+vector_zext in one instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126080 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/LangRef.html b/docs/LangRef.html
index fa6a07846533dba5b2af6a81c10c97da31002f3b..81fa8cc6e89d827a3c018d845fcb82ccb2881173 100644 (file)
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -4614,10 +4614,11 @@ entry:
 
 
 <h5>Arguments:</h5>
-<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
-   <a href="#t_integer">integer</a> type, and a type to cast it to, which must
-   also be of <a href="#t_integer">integer</a> type. The bit size of the
-   <tt>value</tt> must be smaller than the bit size of the destination type,
+<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
+   Both types must be of <a href="#t_integer">integer</a> types, or vectors
+   of the same number of integers.
+   The bit size of the <tt>value</tt> must be smaller than
+   the bit size of the destination type,
    <tt>ty2</tt>.</p>
 
 <h5>Semantics:</h5>
@@ -4630,6 +4631,7 @@ entry:
 <pre>
   %X = zext i32 257 to i64              <i>; yields i64:257</i>
   %Y = zext i1 true to i32              <i>; yields i32:1</i>
+  %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
 </pre>
 
 </div>

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 90356021f60225aaedf863923ad95de8e3b5678c..c5f0324ac41611d212aaf1bdb939d0edab8747d4 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3887,7 +3887,9 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
   }
 
   // fold (zext (load x)) -> (zext (truncate (zextload x)))
-  if (ISD::isNON_EXTLoad(N0.getNode()) &&
+  // None of the supported targets knows how to perform load and vector_zext
+  // in one instruction.  We only perform this transformation on scalar zext.
+  if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() &&
       ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
        TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) {
     bool DoXform = true;

diff --git a/test/CodeGen/X86/vec_zext.ll b/test/CodeGen/X86/vec_zext.ll
new file mode 100644 (file)
index 0000000..615a50b
--- /dev/null
+++ b/test/CodeGen/X86/vec_zext.ll
@@ -0,0 +1,69 @@
+; RUN: llc < %s -march=x86-64
+; PR 9267
+
+define<4 x i32> @func_16_32() {
+  %F = load <4 x i16>* undef
+  %G = zext <4 x i16> %F to <4 x i32>
+  %H = load <4 x i16>* undef
+  %Y = zext <4 x i16> %H to <4 x i32>
+  %T = add <4 x i32> %Y, %G
+  store <4 x i32>%T , <4 x i32>* undef
+  ret <4 x i32> %T
+}
+
+define<4 x i64> @func_16_64() {
+  %F = load <4 x i16>* undef
+  %G = zext <4 x i16> %F to <4 x i64>
+  %H = load <4 x i16>* undef
+  %Y = zext <4 x i16> %H to <4 x i64>
+  %T = xor <4 x i64> %Y, %G
+  store <4 x i64>%T , <4 x i64>* undef
+  ret <4 x i64> %T
+}
+
+define<4 x i64> @func_32_64() {
+  %F = load <4 x i32>* undef
+  %G = zext <4 x i32> %F to <4 x i64>
+  %H = load <4 x i32>* undef
+  %Y = zext <4 x i32> %H to <4 x i64>
+  %T = or <4 x i64> %Y, %G
+  ret <4 x i64> %T
+}
+
+define<4 x i16> @func_8_16() {
+  %F = load <4 x i8>* undef
+  %G = zext <4 x i8> %F to <4 x i16>
+  %H = load <4 x i8>* undef
+  %Y = zext <4 x i8> %H to <4 x i16>
+  %T = add <4 x i16> %Y, %G
+  ret <4 x i16> %T
+}
+
+define<4 x i32> @func_8_32() {
+  %F = load <4 x i8>* undef
+  %G = zext <4 x i8> %F to <4 x i32>
+  %H = load <4 x i8>* undef
+  %Y = zext <4 x i8> %H to <4 x i32>
+  %T = sub <4 x i32> %Y, %G
+  ret <4 x i32> %T
+}
+
+define<4 x i64> @func_8_64() {
+  %F = load <4 x i8>* undef
+  %G = zext <4 x i8> %F to <4 x i64>
+  %H = load <4 x i8>* undef
+  %Y = zext <4 x i8> %H to <4 x i64>
+  %T = add <4 x i64> %Y, %G
+  ret <4 x i64> %T
+}
+
+define<4 x i32> @const_16_32() {
+  %G = zext <4 x i16> <i16 0, i16 3, i16 8, i16 7> to <4 x i32>
+  ret <4 x i32> %G
+}
+
+define<4 x i64> @const_16_64() {
+  %G = zext <4 x i16> <i16 0, i16 3, i16 8, i16 7> to <4 x i64>
+  ret <4 x i64> %G
+}
+