teach tblgen to allow patterns like (add (i32 (bitconvert (i32 GPR))), 4),

transforming it into (add (i32 GPR), 4).  This allows us to write type
generic multi patterns and have tblgen automatically drop the bitconvert
in the case when the types align.  This allows us to fold an extra load
in the changed testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99756 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/X86/2007-04-25-MMX-PADDQ.ll b/test/CodeGen/X86/2007-04-25-MMX-PADDQ.ll
index 113d0eb8647fc73a7bbe1146473a3d8a48d8d3fb..c39b82a1fe3606779dde0f37beaf0c2c73f51fb8 100644 (file)
--- a/test/CodeGen/X86/2007-04-25-MMX-PADDQ.ll
+++ b/test/CodeGen/X86/2007-04-25-MMX-PADDQ.ll
@@ -1,12 +1,16 @@
-; RUN: llc < %s -o - -march=x86 -mattr=+mmx | grep paddq | count 2
-; RUN: llc < %s -o - -march=x86 -mattr=+mmx | grep movq | count 2
+; RUN: llc < %s -o - -march=x86 -mattr=+mmx | FileCheck %s
 
-define <1 x i64> @unsigned_add3(<1 x i64>* %a, <1 x i64>* %b, i32 %count) {
+define <1 x i64> @unsigned_add3(<1 x i64>* %a, <1 x i64>* %b, i32 %count) nounwind {
 entry:
        %tmp2942 = icmp eq i32 %count, 0                ; <i1> [#uses=1]
        br i1 %tmp2942, label %bb31, label %bb26
 
 bb26:          ; preds = %bb26, %entry
+
+; CHECK:  movq ({{.*}},8), %mm
+; CHECK:  paddq        ({{.*}},8), %mm
+; CHECK:  paddq        %mm{{[0-7]}}, %mm
+
        %i.037.0 = phi i32 [ 0, %entry ], [ %tmp25, %bb26 ]             ; <i32> [#uses=3]
        %sum.035.0 = phi <1 x i64> [ zeroinitializer, %entry ], [ %tmp22, %bb26 ]               ; <<1 x i64>> [#uses=1]
        %tmp13 = getelementptr <1 x i64>* %b, i32 %i.037.0              ; <<1 x i64>*> [#uses=1]

diff --git a/utils/TableGen/CodeGenDAGPatterns.cpp b/utils/TableGen/CodeGenDAGPatterns.cpp
index 6bb239ac69af92b577738622299991e47f4c770a..a29c5539fc84e257fe0f81326bb13fe396479b9e 100644 (file)
--- a/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -1591,6 +1591,40 @@ TreePatternNode *TreePattern::ParseTreePattern(Init *TheInit, StringRef OpName){
   return Result;
 }
 
+/// SimplifyTree - See if we can simplify this tree to eliminate something that
+/// will never match in favor of something obvious that will.  This is here
+/// strictly as a convenience to target authors because it allows them to write
+/// more type generic things and have useless type casts fold away.
+///
+/// This returns true if any change is made.
+static bool SimplifyTree(TreePatternNode *&N) {
+  if (N->isLeaf())
+    return false;
+
+  // If we have a bitconvert with a resolved type and if the source and
+  // destination types are the same, then the bitconvert is useless, remove it.
+  if (N->getOperator()->getName() == "bitconvert" &&
+      N->getNumChildren() > 0 && // FIXME
+      N->getExtType(0).isConcrete() &&
+      N->getExtType(0) == N->getChild(0)->getExtType(0) &&
+      N->getName().empty()) {
+    N = N->getChild(0);
+    SimplifyTree(N);
+    return true;
+  }
+
+  // Walk all children.
+  bool MadeChange = false;
+  for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i) {
+    TreePatternNode *Child = N->getChild(i);
+    MadeChange |= SimplifyTree(Child);
+    N->setChild(i, Child);
+  }
+  return MadeChange;
+}
+
+
+
 /// InferAllTypes - Infer/propagate as many types throughout the expression
 /// patterns as possible.  Return true if all types are inferred, false
 /// otherwise.  Throw an exception if a type contradiction is found.
@@ -1602,8 +1636,10 @@ InferAllTypes(const StringMap<SmallVector<TreePatternNode*,1> > *InNamedTypes) {
   bool MadeChange = true;
   while (MadeChange) {
     MadeChange = false;
-    for (unsigned i = 0, e = Trees.size(); i != e; ++i)
+    for (unsigned i = 0, e = Trees.size(); i != e; ++i) {
       MadeChange |= Trees[i]->ApplyTypeConstraints(*this, false);
+      MadeChange |= SimplifyTree(Trees[i]);
+    }
 
     // If there are constraints on our named nodes, apply them.
     for (StringMap<SmallVector<TreePatternNode*,1> >::iterator