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| -rw-r--r-- | lib/Target/PowerPC/README.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt index 580affb688..2897655d2d 100644 --- a/lib/Target/PowerPC/README.txt +++ b/lib/Target/PowerPC/README.txt @@ -222,3 +222,22 @@ The two-addr pass or RA needs to learn when it is profitable to commute an instruction to avoid a copy AFTER the 2-addr instruction. The 2-addr pass currently only commutes to avoid inserting a copy BEFORE the two addr instr. +===-------------------------------------------------------------------------=== + +Compile offsets from allocas: + +int *%test() { + %X = alloca { int, int } + %Y = getelementptr {int,int}* %X, int 0, uint 1 + ret int* %Y +} + +into a single add, not two: + +_test: + addi r2, r1, -8 + addi r3, r2, 4 + blr + +--> important for C++. + |