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| -rw-r--r-- | lib/Target/README.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index 64c1c55fd4..d61473136f 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -64,3 +64,15 @@ Number 1 is the preferred solution. //===---------------------------------------------------------------------===// +DAG combine this into mul A, 8: + +int %test(int %A) { + %B = mul int %A, 8 ;; shift + %C = add int %B, 7 ;; dead, no demanded bits. + %D = and int %C, -8 ;; dead once add is gone. + ret int %D +} + +This sort of thing occurs in the alloca lowering code and other places that +are generating alignment of an already aligned value. + |