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| -rw-r--r-- | lib/Target/ARM/README.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/Target/ARM/README.txt b/lib/Target/ARM/README.txt index f05ae1c423..1fb775064e 100644 --- a/lib/Target/ARM/README.txt +++ b/lib/Target/ARM/README.txt @@ -573,3 +573,22 @@ __Z11no_overflowjj: bx lr //===---------------------------------------------------------------------===// + +Easy ARM microoptimization (with -mattr=+vfp2): + +define i64 @i(double %X) { + %Y = bitcast double %X to i64 + ret i64 %Y +} + +compiles into: + +_i: + fmdrr d0, r0, r1 + fmrrd r0, r1, d0 + bx lr + +This just needs a target-specific dag combine to merge the two ARMISD nodes. + + +//===---------------------------------------------------------------------===// |