[SDAGBuilder] Don't create a binary tree for switches in minsize mode

This bloats codesize - all of the non-leaf nodes are extra code.

llvm-svn: 280932

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index e037108..5e9bc0d 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -9237,7 +9237,8 @@ void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) {
     WorkList.pop_back();
     unsigned NumClusters = W.LastCluster - W.FirstCluster + 1;
 
-    if (NumClusters > 3 && TM.getOptLevel() != CodeGenOpt::None) {
+    if (NumClusters > 3 && TM.getOptLevel() != CodeGenOpt::None &&
+        !DefaultMBB->getParent()->getFunction()->optForMinSize()) {
       // For optimized builds, lower large range as a balanced binary tree.
       splitWorkItem(WorkList, W, SI.getCondition(), SwitchMBB);
       continue;

diff --git a/llvm/test/CodeGen/ARM/switch-minsize.ll b/llvm/test/CodeGen/ARM/switch-minsize.ll
new file mode 100644 (file)
index 0000000..92af6b3
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/switch-minsize.ll
@@ -0,0 +1,34 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:o-p:32:32-f64:32:64-v64:32:64-v128:32:128-a:0:32-n32-S32"
+target triple = "thumbv7-apple-ios8.0.0"
+
+; CHECK: beq
+; CHECK: beq
+; CHECK: beq
+; CHECK: cbnz
+declare void @g(i32)
+define void @f(i32 %val) optsize minsize {
+  switch i32 %val, label %def [
+    i32 0, label %one
+    i32 9, label %two
+    i32 994, label %three
+    i32 1154, label %four
+  ]
+  
+one:
+  call void @g(i32 1)
+  ret void
+two:
+  call void @g(i32 001)
+  ret void
+three:
+  call void @g(i32 78)
+  ret void
+four:
+  call void @g(i32 87)
+  ret void
+def:
+  call void @g(i32 11)
+  ret void
+}