[PATCH] D42526: [X86][XOP] Update isVectorShiftByScalarCheap with cases covered by XOP

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: zvi, craig.topper, spatel.
Herald added subscribers: tschuett, rengolin.

Similar to https://reviews.llvm.org/D42437, XOP support variable shift for v16i8/v8i16/v4i32/v2i64 types.


Repository:
  rL LLVM

https://reviews.llvm.org/D42526

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/Transforms/CodeGenPrepare/X86/x86-shuffle-sink.ll


Index: test/Transforms/CodeGenPrepare/X86/x86-shuffle-sink.ll
===================================================================
--- test/Transforms/CodeGenPrepare/X86/x86-shuffle-sink.ll
+++ test/Transforms/CodeGenPrepare/X86/x86-shuffle-sink.ll
@@ -45,8 +45,7 @@
 ; CHECK-XOP:       if_true:
 ; CHECK-XOP-NEXT:    ret <8 x i16> [[MASK]]
 ; CHECK-XOP:       if_false:
-; CHECK-XOP-NEXT:    [[TMP1:%.*]] = shufflevector <8 x i16> [[TMP]], <8 x i16> undef, <8 x i32> zeroinitializer
-; CHECK-XOP-NEXT:    [[RES:%.*]] = shl <8 x i16> [[LHS:%.*]], [[TMP1]]
+; CHECK-XOP-NEXT:    [[RES:%.*]] = shl <8 x i16> [[LHS:%.*]], [[MASK]]
 ; CHECK-XOP-NEXT:    ret <8 x i16> [[RES]]
 ;
 ; CHECK-AVX2-LABEL: @test_16bit(
@@ -117,8 +116,7 @@
 ; CHECK-XOP:       if_true:
 ; CHECK-XOP-NEXT:    ret <4 x i32> [[MASK]]
 ; CHECK-XOP:       if_false:
-; CHECK-XOP-NEXT:    [[TMP1:%.*]] = shufflevector <4 x i32> [[TMP]], <4 x i32> undef, <4 x i32> <i32 0, i32 undef, i32 0, i32 0>
-; CHECK-XOP-NEXT:    [[RES:%.*]] = ashr <4 x i32> [[LHS:%.*]], [[TMP1]]
+; CHECK-XOP-NEXT:    [[RES:%.*]] = ashr <4 x i32> [[LHS:%.*]], [[MASK]]
 ; CHECK-XOP-NEXT:    ret <4 x i32> [[RES]]
 ;
 ; CHECK-AVX-LABEL: @test_32bit(
@@ -158,8 +156,7 @@
 ; CHECK-XOP:       if_true:
 ; CHECK-XOP-NEXT:    ret <2 x i64> [[MASK]]
 ; CHECK-XOP:       if_false:
-; CHECK-XOP-NEXT:    [[TMP1:%.*]] = shufflevector <2 x i64> [[TMP]], <2 x i64> undef, <2 x i32> zeroinitializer
-; CHECK-XOP-NEXT:    [[RES:%.*]] = lshr <2 x i64> [[LHS:%.*]], [[TMP1]]
+; CHECK-XOP-NEXT:    [[RES:%.*]] = lshr <2 x i64> [[LHS:%.*]], [[MASK]]
 ; CHECK-XOP-NEXT:    ret <2 x i64> [[RES]]
 ;
 ; CHECK-AVX-LABEL: @test_64bit(
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -25676,6 +25676,11 @@
   if (Bits == 8)
     return false;
 
+  // XOP has v16i8/v8i16/v4i32/v2i64 variable vector shifts.
+  if (Subtarget.hasXOP() && Ty->getPrimitiveSizeInBits() == 128 &&
+      (Bits == 8 || Bits == 16 || Bits == 32 || Bits == 64))
+    return false;
+
   // AVX2 has vpsllv[dq] instructions (and other shifts) that make variable
   // shifts just as cheap as scalar ones.
   if (Subtarget.hasAVX2() && (Bits == 32 || Bits == 64))


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