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authorDan Gohman <gohman@apple.com>2008-09-24 23:44:12 +0000
committerDan Gohman <gohman@apple.com>2008-09-24 23:44:12 +0000
commit382e2ec6b7acc68229d9ca666aefc42c46eeaa4c (patch)
treee37913150c7eacbfa8acadc6717b1acb6894b860 /llvm/lib/CodeGen
parentf17c232a9eff4b2c3b2de9834db93a101d46621b (diff)
downloadbcm5719-llvm-382e2ec6b7acc68229d9ca666aefc42c46eeaa4c.tar.gz
bcm5719-llvm-382e2ec6b7acc68229d9ca666aefc42c46eeaa4c.zip
Give LowerSubregs.cpp a top-level description.
llvm-svn: 56596
Diffstat (limited to 'llvm/lib/CodeGen')
-rw-r--r--llvm/lib/CodeGen/LowerSubregs.cpp7
1 files changed, 7 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/LowerSubregs.cpp b/llvm/lib/CodeGen/LowerSubregs.cpp
index 00038d5c1c7..f9cef4ccfb7 100644
--- a/llvm/lib/CodeGen/LowerSubregs.cpp
+++ b/llvm/lib/CodeGen/LowerSubregs.cpp
@@ -6,6 +6,13 @@
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
+//
+// This file defines a MachineFunction pass which runs after register
+// allocation that turns subreg insert/extract instructions into register
+// copies, as needed. This ensures correct codegen even if the coalescer
+// isn't able to remove all subreg instructions.
+//
+//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "lowersubregs"
#include "llvm/CodeGen/Passes.h"
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