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-rw-r--r--llvm/lib/Target/X86/X86ISelLowering.cpp33
-rw-r--r--llvm/test/CodeGen/X86/avx-shift.ll4
-rw-r--r--llvm/test/CodeGen/X86/vec_shift6.ll134
3 files changed, 169 insertions, 2 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 85656d80914..4ce2ea36c00 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -13156,6 +13156,39 @@ static SDValue LowerShift(SDValue Op, const X86Subtarget* Subtarget,
return Op;
}
+ // If possible, lower this packed shift into a vector multiply instead of
+ // expanding it into a sequence of scalar shifts.
+ // Do this only if the vector shift count is a constant build_vector.
+ if (Op.getOpcode() == ISD::SHL &&
+ (VT == MVT::v8i16 || VT == MVT::v4i32 ||
+ (Subtarget->hasInt256() && VT == MVT::v16i16)) &&
+ ISD::isBuildVectorOfConstantSDNodes(Amt.getNode())) {
+ SmallVector<SDValue, 8> Elts;
+ EVT SVT = VT.getScalarType();
+ unsigned SVTBits = SVT.getSizeInBits();
+ const APInt &One = APInt(SVTBits, 1);
+ unsigned NumElems = VT.getVectorNumElements();
+
+ for (unsigned i=0; i !=NumElems; ++i) {
+ SDValue Op = Amt->getOperand(i);
+ if (Op->getOpcode() == ISD::UNDEF) {
+ Elts.push_back(Op);
+ continue;
+ }
+
+ ConstantSDNode *ND = cast<ConstantSDNode>(Op);
+ const APInt &C = APInt(SVTBits, ND->getAPIntValue().getZExtValue());
+ uint64_t ShAmt = C.getZExtValue();
+ if (ShAmt >= SVTBits) {
+ Elts.push_back(DAG.getUNDEF(SVT));
+ continue;
+ }
+ Elts.push_back(DAG.getConstant(One.shl(ShAmt), SVT));
+ }
+ SDValue BV = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Elts[0], NumElems);
+ return DAG.getNode(ISD::MUL, dl, VT, R, BV);
+ }
+
// Lower SHL with variable shift amount.
if (VT == MVT::v4i32 && Op->getOpcode() == ISD::SHL) {
Op = DAG.getNode(ISD::SHL, dl, VT, Amt, DAG.getConstant(23, VT));
diff --git a/llvm/test/CodeGen/X86/avx-shift.ll b/llvm/test/CodeGen/X86/avx-shift.ll
index d79dfcc076b..a70d45a7991 100644
--- a/llvm/test/CodeGen/X86/avx-shift.ll
+++ b/llvm/test/CodeGen/X86/avx-shift.ll
@@ -115,8 +115,8 @@ define <8 x i32> @vshift08(<8 x i32> %a) nounwind {
; PR15141
; CHECK: _vshift13:
; CHECK-NOT: vpsll
-; CHECK: vcvttps2dq
-; CHECK-NEXT: vpmulld
+; CHECK-NOT: vcvttps2dq
+; CHECK: vpmulld
define <4 x i32> @vshift13(<4 x i32> %in) {
%T = shl <4 x i32> %in, <i32 0, i32 1, i32 2, i32 4>
ret <4 x i32> %T
diff --git a/llvm/test/CodeGen/X86/vec_shift6.ll b/llvm/test/CodeGen/X86/vec_shift6.ll
new file mode 100644
index 00000000000..df2d9cb0468
--- /dev/null
+++ b/llvm/test/CodeGen/X86/vec_shift6.ll
@@ -0,0 +1,134 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 | FileCheck %s -check-prefix=CHECK -check-prefix=SSE
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=core-avx2 | FileCheck %s -check-prefix=CHECK -check-prefix=AVX2 -check-prefix=AVX2ONLY
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=knl | FileCheck %s -check-prefix=CHECK -check-prefix=AVX2 -check-prefix=AVX512
+
+
+; Verify that we don't scalarize a packed vector shift left of 16-bit
+; signed integers if the amount is a constant build_vector.
+; Check that we produce a SSE2 packed integer multiply (pmullw) instead.
+
+define <8 x i16> @test1(<8 x i16> %a) {
+ %shl = shl <8 x i16> %a, <i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11>
+ ret <8 x i16> %shl
+}
+; CHECK-LABEL: test1
+; CHECK: pmullw
+; CHECK-NEXT: ret
+
+
+define <8 x i16> @test2(<8 x i16> %a) {
+ %shl = shl <8 x i16> %a, <i16 0, i16 undef, i16 0, i16 0, i16 1, i16 undef, i16 -1, i16 1>
+ ret <8 x i16> %shl
+}
+; CHECK-LABEL: test2
+; CHECK: pmullw
+; CHECK-NEXT: ret
+
+
+; Verify that a vector shift left of 32-bit signed integers is simply expanded
+; into a SSE4.1 pmulld (instead of cvttps2dq + pmulld) if the vector of shift
+; counts is a constant build_vector.
+
+define <4 x i32> @test3(<4 x i32> %a) {
+ %shl = shl <4 x i32> %a, <i32 1, i32 -1, i32 2, i32 -3>
+ ret <4 x i32> %shl
+}
+; CHECK-LABEL: test3
+; CHECK-NOT: cvttps2dq
+; SSE: pmulld
+; AVX2: vpsllvd
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test4(<4 x i32> %a) {
+ %shl = shl <4 x i32> %a, <i32 0, i32 0, i32 1, i32 1>
+ ret <4 x i32> %shl
+}
+; CHECK-LABEL: test4
+; CHECK-NOT: cvttps2dq
+; SSE: pmulld
+; AVX2: vpsllvd
+; CHECK-NEXT: ret
+
+
+; If we have AVX/SSE2 but not AVX2, verify that the following shift is split
+; into two pmullw instructions. With AVX2, the test case below would produce
+; a single vpmullw.
+
+define <16 x i16> @test5(<16 x i16> %a) {
+ %shl = shl <16 x i16> %a, <i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11, i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11>
+ ret <16 x i16> %shl
+}
+; CHECK-LABEL: test5
+; SSE: pmullw
+; SSE-NEXT: pmullw
+; AVX2: vpmullw
+; AVX2-NOT: vpmullw
+; CHECK: ret
+
+
+; If we have AVX/SSE4.1 but not AVX2, verify that the following shift is split
+; into two pmulld instructions. With AVX2, the test case below would produce
+; a single vpsllvd instead.
+
+define <8 x i32> @test6(<8 x i32> %a) {
+ %shl = shl <8 x i32> %a, <i32 1, i32 1, i32 2, i32 3, i32 1, i32 1, i32 2, i32 3>
+ ret <8 x i32> %shl
+}
+; CHECK-LABEL: test6
+; SSE: pmulld
+; SSE-NEXT: pmulld
+; AVX2: vpsllvd
+; CHECK: ret
+
+
+; With AVX2 and AVX512, the test case below should produce a sequence of
+; two vpmullw instructions. On SSE2 instead, we split the shift in four
+; parts and then we convert each part into a pmullw.
+
+define <32 x i16> @test7(<32 x i16> %a) {
+ %shl = shl <32 x i16> %a, <i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11, i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11, i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11, i16 1, i16 1, i16 2, i16 3, i16 7, i16 0, i16 9, i16 11>
+ ret <32 x i16> %shl
+}
+; CHECK-LABEL: test7
+; SSE: pmullw
+; SSE-NEXT: pmullw
+; SSE-NEXT: pmullw
+; SSE-NEXT: pmullw
+; AVX2: vpmullw
+; AVX2-NEXT: vpmullw
+; CHECK: ret
+
+
+; Similar to test7; the difference is that with AVX512 support
+; we only produce a single vpsllvd/vpsllvq instead of a pair of vpsllvd/vpsllvq.
+
+define <16 x i32> @test8(<16 x i32> %a) {
+ %shl = shl <16 x i32> %a, <i32 1, i32 1, i32 2, i32 3, i32 1, i32 1, i32 2, i32 3, i32 1, i32 1, i32 2, i32 3, i32 1, i32 1, i32 2, i32 3>
+ ret <16 x i32> %shl
+}
+; CHECK-LABEL: test8
+; SSE: pmulld
+; SSE-NEXT: pmulld
+; SSE-NEXT: pmulld
+; SSE-NEXT: pmulld
+; AVX2ONLY: vpsllvd
+; AVX2ONLY-NEXT: vpsllvd
+; AVX512: vpsllvd
+; AVX512-NOT: vpsllvd
+; CHECK: ret
+
+
+; The shift from 'test9' gets scalarized if we don't have AVX2/AVX512f support.
+
+define <8 x i64> @test9(<8 x i64> %a) {
+ %shl = shl <8 x i64> %a, <i64 1, i64 1, i64 2, i64 3, i64 1, i64 1, i64 2, i64 3>
+ ret <8 x i64> %shl
+}
+; CHECK-LABEL: test9
+; AVX2ONLY: vpsllvq
+; AVX2ONLY-NEXT: vpsllvq
+; AVX512: vpsllvq
+; AVX512-NOT: vpsllvq
+; CHECK: ret
+
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