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| author | Chris Lattner <sabre@nondot.org> | 2010-09-19 00:34:58 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-09-19 00:34:58 +0000 |
| commit | 702917d4e836ec8346c05aadbc2c1a461c6c3ca6 (patch) | |
| tree | 9a10a85d883e4c3cf28e7ca464ba3fd7be3822e3 | |
| parent | 222920d667f848de3c51cd93496de980ffcf2e6a (diff) | |
| download | external_llvm-702917d4e836ec8346c05aadbc2c1a461c6c3ca6.zip external_llvm-702917d4e836ec8346c05aadbc2c1a461c6c3ca6.tar.gz external_llvm-702917d4e836ec8346c05aadbc2c1a461c6c3ca6.tar.bz2 | |
add a readme.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114303 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/PowerPC/README.txt | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt index 3465779..4c80225 100644 --- a/lib/Target/PowerPC/README.txt +++ b/lib/Target/PowerPC/README.txt @@ -37,6 +37,31 @@ _f3: ori r3, r2, 65535 blr +===-------------------------------------------------------------------------=== + +This code: + +unsigned add32carry(unsigned sum, unsigned x) { + unsigned z = sum + x; + if (sum + x < x) + z++; + return z; +} + +Should compile to something like: + + addc r3,r3,r4 + addze r3,r3 + +instead we get: + + add r3, r4, r3 + cmplw cr7, r3, r4 + mfcr r4 ; 1 + rlwinm r4, r4, 29, 31, 31 + add r3, r3, r4 + +Ick. ===-------------------------------------------------------------------------=== |