[MIPS GlobalISel] NarrowScalar G_MUL

Narrow Scalar G_MUL for MIPS32.
Revisit NarrowScalar implementation in LegalizerHelper.
Introduce new helper function multiplyRegisters.
It performs generic multiplication of values held in multiple registers.
Generated instructions use only types NarrowTy and i1.
Destination can be same or two times size of the source.

Differential Revision: https://reviews.llvm.org/D58824

llvm-svn: 355814

1 files changed, 1 insertions, 5 deletions

diff --git a/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp b/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
index 1da43b0b6df..99f98dfabd2 100644
--- a/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
@@ -24,14 +24,10 @@ MipsLegalizerInfo::MipsLegalizerInfo(const MipsSubtarget &ST) {
   const LLT s64 = LLT::scalar(64);
   const LLT p0 = LLT::pointer(0, 32);
 
-  getActionDefinitionsBuilder({G_ADD, G_SUB})
+  getActionDefinitionsBuilder({G_ADD, G_SUB, G_MUL})
       .legalFor({s32})
       .clampScalar(0, s32, s32);
 
-  getActionDefinitionsBuilder(G_MUL)
-      .legalFor({s32})
-      .minScalar(0, s32);
-
   getActionDefinitionsBuilder({G_UADDO, G_UADDE, G_USUBO, G_USUBE, G_UMULO})
       .lowerFor({{s32, s1}});