[cfe-commits] r126638 - in /cfe/trunk: lib/CodeGen/CGStmt.cpp test/CodeGen/switch-dce.c

[Chris Lattner]

Author: lattner
Date: Mon Feb 28 01:16:14 2011
New Revision: 126638

URL: http://llvm.org/viewvc/llvm-project?rev=126638&view=rev
Log:
make switch constant folding a bit stronger, handling a missed case.

Modified:
    cfe/trunk/lib/CodeGen/CGStmt.cpp
    cfe/trunk/test/CodeGen/switch-dce.c

Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=126638&r1=126637&r2=126638&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGStmt.cpp Mon Feb 28 01:16:14 2011
@@ -895,9 +895,14 @@
         case CSFC_Success:
           // A successful result means that either 1) that the statement doesn't
           // have the case and is skippable, or 2) does contain the case value
-          // and also contains the break to exit the switch.  In either case,
-          // we continue scanning the body of the compound statement to see if
-          // the rest are skippable or have the case.
+          // and also contains the break to exit the switch.  In the later case,
+          // we just verify the rest of the statements are elidable.
+          if (FoundCase) {
+            for (++I; I != E; ++I)
+              if (CodeGenFunction::ContainsLabel(*I, true))
+                return CSFC_Failure;
+            return CSFC_Success;
+          }
           break;
         case CSFC_FallThrough:
           // If we have a fallthrough condition, then we must have found the

Modified: cfe/trunk/test/CodeGen/switch-dce.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/switch-dce.c?rev=126638&r1=126637&r2=126638&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/switch-dce.c (original)
+++ cfe/trunk/test/CodeGen/switch-dce.c Mon Feb 28 01:16:14 2011
@@ -167,7 +167,9 @@
   } 
 }
 
-
+// CHECK: @test10
+// CHECK-NOT: switch
+// CHECK: ret i32
 int test10(void) {
 	switch(8) {
 		case 8:
@@ -180,3 +182,17 @@
 	
 	return 0;
 }
+
+// CHECK: @test11
+// CHECK-NOT: switch
+// CHECK: ret void
+void test11() {
+  switch (1) {
+    case 1:
+      break;
+    case 42: ;
+      int x;  // eliding var decl?
+      x = 4;
+      break;
+  }
+}