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authorAnders Carlsson <andersca@mac.com>2011-01-16 21:26:15 +0000
committerAnders Carlsson <andersca@mac.com>2011-01-16 21:26:15 +0000
commit5822b86e4dc493f2fb7416a9aea0f51143d8e475 (patch)
treee5d3e044d9b3f5f66d60fe62c21f2fb3ae47e529 /lib/Target/README.txt
parent0599c6bb3c9c3817600021f31f16eb49e57ea9d8 (diff)
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Update README.txt to remove the DAE enhancement.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123597 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/README.txt')
-rw-r--r--lib/Target/README.txt23
1 files changed, 0 insertions, 23 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt
index 6ba0d745f6..6c8187cdbf 100644
--- a/lib/Target/README.txt
+++ b/lib/Target/README.txt
@@ -2,29 +2,6 @@ Target Independent Opportunities:
//===---------------------------------------------------------------------===//
-Dead argument elimination should be enhanced to handle cases when an argument is
-dead to an externally visible function. Though the argument can't be removed
-from the externally visible function, the caller doesn't need to pass it in.
-For example in this testcase:
-
- void foo(int X) __attribute__((noinline));
- void foo(int X) { sideeffect(); }
- void bar(int A) { foo(A+1); }
-
-We compile bar to:
-
-define void @bar(i32 %A) nounwind ssp {
- %0 = add nsw i32 %A, 1 ; <i32> [#uses=1]
- tail call void @foo(i32 %0) nounwind noinline ssp
- ret void
-}
-
-The add is dead, we could pass in 'i32 undef' instead. This occurs for C++
-templates etc, which usually have linkonce_odr/weak_odr linkage, not internal
-linkage.
-
-//===---------------------------------------------------------------------===//
-
With the recent changes to make the implicit def/use set explicit in
machineinstrs, we should change the target descriptions for 'call' instructions
so that the .td files don't list all the call-clobbered registers as implicit