commit 365be4f95ccf9ab1cf217609678159acbe6b01a5
author Simon Pilgrim <llvm-dev@redking.me.uk> Thu Oct 20 18:00:35 2016 +0000
committer Simon Pilgrim <llvm-dev@redking.me.uk> Thu Oct 20 18:00:35 2016 +0000
tree dfe49b348986033c18ab25512672fe7dc6c64d8d
parent 493091fdefc28ee4f64ae3640771237a0368ba72

[CostModel][X86] Fixed AVX1/AVX512 sdiv/udiv uniformconst costs for 256/512 bit integer vectors

We weren't checking for uniform const costs before the general cost, resulting in very high estimates.

llvm-svn: 284755

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 11bce7c..e142208 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -140,6 +140,30 @@
     return Cost;
   }
 
+  static const CostTblEntry AVX512BWUniformConstCostTable[] = {
+    { ISD::SDIV, MVT::v32i16,  6 }, // vpmulhw sequence
+    { ISD::UDIV, MVT::v32i16,  6 }, // vpmulhuw sequence
+  };
+
+  if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
+      ST->hasBWI()) {
+    if (const auto *Entry = CostTableLookup(AVX512BWUniformConstCostTable, ISD,
+                                            LT.second))
+      return LT.first * Entry->Cost;
+  }
+
+  static const CostTblEntry AVX512UniformConstCostTable[] = {
+    { ISD::SDIV, MVT::v16i32, 15 }, // vpmuldq sequence
+    { ISD::UDIV, MVT::v16i32, 15 }, // vpmuludq sequence
+  };
+
+  if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
+      ST->hasAVX512()) {
+    if (const auto *Entry = CostTableLookup(AVX512UniformConstCostTable, ISD,
+                                            LT.second))
+      return LT.first * Entry->Cost;
+  }
+
   static const CostTblEntry AVX2UniformConstCostTable[] = {
     { ISD::SRA,  MVT::v4i64,   4 }, // 2 x psrad + shuffle.
 
@@ -156,6 +180,30 @@
       return LT.first * Entry->Cost;
   }
 
+  static const CostTblEntry SSE2UniformConstCostTable[] = {
+    { ISD::SDIV, MVT::v16i16, 12 }, // pmulhw sequence
+    { ISD::SDIV, MVT::v8i16,   6 }, // pmulhw sequence
+    { ISD::UDIV, MVT::v16i16, 12 }, // pmulhuw sequence
+    { ISD::UDIV, MVT::v8i16,   6 }, // pmulhuw sequence
+    { ISD::SDIV, MVT::v8i32,  38 }, // pmuludq sequence
+    { ISD::SDIV, MVT::v4i32,  19 }, // pmuludq sequence
+    { ISD::UDIV, MVT::v8i32,  30 }, // pmuludq sequence
+    { ISD::UDIV, MVT::v4i32,  15 }, // pmuludq sequence
+  };
+
+  if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
+      ST->hasSSE2()) {
+    // pmuldq sequence.
+    if (ISD == ISD::SDIV && LT.second == MVT::v8i32 && ST->hasAVX())
+      return LT.first * 30;
+    if (ISD == ISD::SDIV && LT.second == MVT::v4i32 && ST->hasSSE41())
+      return LT.first * 15;
+
+    if (const auto *Entry = CostTableLookup(SSE2UniformConstCostTable, ISD,
+                                            LT.second))
+      return LT.first * Entry->Cost;
+  }
+
   static const CostTblEntry AVX512BWCostTable[] = {
     // Vectorizing division is a bad idea. See the SSE2 table for more comments.
     { ISD::SDIV,  MVT::v64i8,  64*20 },
@@ -292,15 +340,6 @@
   }
 
   static const CostTblEntry
-  SSE2UniformConstCostTable[] = {
-    // Constant splats are cheaper for the following instructions.
-    { ISD::SDIV, MVT::v8i16,  6 }, // pmulhw sequence
-    { ISD::UDIV, MVT::v8i16,  6 }, // pmulhuw sequence
-    { ISD::SDIV, MVT::v4i32, 19 }, // pmuludq sequence
-    { ISD::UDIV, MVT::v4i32, 15 }, // pmuludq sequence
-  };
-
-  static const CostTblEntry
   SSE2UniformCostTable[] = {
     // Uniform splats are cheaper for the following instructions.
     { ISD::SHL,  MVT::v16i8,  1 }, // psllw.
@@ -334,14 +373,6 @@
   if (ST->hasSSE2() &&
       ((Op2Info == TargetTransformInfo::OK_UniformConstantValue) ||
        (Op2Info == TargetTransformInfo::OK_UniformValue))) {
-    if (Op2Info == TargetTransformInfo::OK_UniformConstantValue) {
-      // pmuldq sequence.
-      if (ISD == ISD::SDIV && LT.second == MVT::v4i32 && ST->hasSSE41())
-        return LT.first * 15;
-      if (const auto *Entry =
-              CostTableLookup(SSE2UniformConstCostTable, ISD, LT.second))
-        return LT.first * Entry->Cost;
-    }
     if (const auto *Entry =
             CostTableLookup(SSE2UniformCostTable, ISD, LT.second))
       return LT.first * Entry->Cost;