Add DAG-combines for aggressive FMA formation.
This patch adds DAG combines to form FMAs from pairs of FADD + FMUL or
FSUB + FMUL. The combines are performed when:
(a) Either
AllowExcessFPPrecision option (-enable-excess-fp-precision for llc)
OR
UnsafeFPMath option (-enable-unsafe-fp-math)
are set, and
(b) TargetLoweringInfo::isFMAFasterThanMulAndAdd(VT) is true for the type of
the FADD/FSUB, and
(c) The FMUL only has one user (the FADD/FSUB).
If your target has fast FMA instructions you can make use of these combines by
overriding TargetLoweringInfo::isFMAFasterThanMulAndAdd(VT) to return true for
types supported by your FMA instruction, and adding patterns to match ISD::FMA
to your FMA instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158757 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/PowerPC/a2-fp-basic.ll b/test/CodeGen/PowerPC/a2-fp-basic.ll
index 932ad7a..a47e662 100644
--- a/test/CodeGen/PowerPC/a2-fp-basic.ll
+++ b/test/CodeGen/PowerPC/a2-fp-basic.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=ppc64 -mcpu=a2 | FileCheck %s
+; RUN: llc < %s -march=ppc64 -mcpu=a2 -enable-excess-fp-precision | FileCheck %s
%0 = type { double, double }