[llvm] r287635 - [SelectionDAG] ComputeNumSignBits of TRUNCATE operations
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 22 03:29:19 PST 2016
Author: rksimon
Date: Tue Nov 22 05:29:19 2016
New Revision: 287635
URL: http://llvm.org/viewvc/llvm-project?rev=287635&view=rev
Log:
[SelectionDAG] ComputeNumSignBits of TRUNCATE operations
Add basic ComputeNumSignBits support for TRUNCATE ops for cases where the source's number of sign bits overlaps with the truncated size.
Improves X86 SIGN_EXTEND_IN_REG vector cases which were needlessly sign extending boolean vector results.
Differential Revision: https://reviews.llvm.org/D26851
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/trunk/test/CodeGen/X86/avx512-mask-op.ll
llvm/trunk/test/CodeGen/X86/psubus.ll
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=287635&r1=287634&r2=287635&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Tue Nov 22 05:29:19 2016
@@ -2843,10 +2843,14 @@ unsigned SelectionDAG::ComputeNumSignBit
Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
if (Tmp == 1) return 1; // Early out.
return std::min(Tmp, Tmp2)-1;
- case ISD::TRUNCATE:
- // FIXME: it's tricky to do anything useful for this, but it is an important
- // case for targets like X86.
+ case ISD::TRUNCATE: {
+ // Check if the sign bits of source go down as far as the truncated value.
+ unsigned NumSrcBits = Op.getOperand(0).getScalarValueSizeInBits();
+ unsigned NumSrcSignBits = ComputeNumSignBits(Op.getOperand(0), Depth + 1);
+ if (NumSrcSignBits > (NumSrcBits - VTBits))
+ return NumSrcSignBits - (NumSrcBits - VTBits);
break;
+ }
case ISD::EXTRACT_ELEMENT: {
const int KnownSign = ComputeNumSignBits(Op.getOperand(0), Depth+1);
const int BitWidth = Op.getValueSizeInBits();
Modified: llvm/trunk/test/CodeGen/X86/avx512-mask-op.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avx512-mask-op.ll?rev=287635&r1=287634&r2=287635&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/avx512-mask-op.ll (original)
+++ llvm/trunk/test/CodeGen/X86/avx512-mask-op.ll Tue Nov 22 05:29:19 2016
@@ -246,12 +246,8 @@ define <4 x i32> @test4(<4 x i64> %x, <4
; KNL: ## BB#0:
; KNL-NEXT: vpcmpgtq %ymm1, %ymm0, %ymm0
; KNL-NEXT: vpmovqd %zmm0, %ymm0
-; KNL-NEXT: vpslld $31, %xmm0, %xmm0
-; KNL-NEXT: vpsrad $31, %xmm0, %xmm0
; KNL-NEXT: vpcmpgtq %ymm3, %ymm2, %ymm1
; KNL-NEXT: vpmovqd %zmm1, %ymm1
-; KNL-NEXT: vpslld $31, %xmm1, %xmm1
-; KNL-NEXT: vpsrad $31, %xmm1, %xmm1
; KNL-NEXT: vpcmpgtd %xmm1, %xmm0, %xmm0
; KNL-NEXT: retq
;
Modified: llvm/trunk/test/CodeGen/X86/psubus.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/psubus.ll?rev=287635&r1=287634&r2=287635&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/psubus.ll (original)
+++ llvm/trunk/test/CodeGen/X86/psubus.ll Tue Nov 22 05:29:19 2016
@@ -601,16 +601,13 @@ define void @test13(i16* nocapture %head
; AVX1-NEXT: vxorps %xmm3, %xmm0, %xmm3
; AVX1-NEXT: vpcmpgtd %xmm6, %xmm3, %xmm3
; AVX1-NEXT: vpacksswb %xmm4, %xmm3, %xmm3
-; AVX1-NEXT: vpsllw $15, %xmm3, %xmm3
-; AVX1-NEXT: vpsraw $15, %xmm3, %xmm3
; AVX1-NEXT: vpsubd %xmm0, %xmm1, %xmm0
; AVX1-NEXT: vpsubd %xmm5, %xmm2, %xmm1
; AVX1-NEXT: vmovdqa {{.*#+}} xmm2 = [0,1,4,5,8,9,12,13,8,9,12,13,12,13,14,15]
; AVX1-NEXT: vpshufb %xmm2, %xmm1, %xmm1
; AVX1-NEXT: vpshufb %xmm2, %xmm0, %xmm0
; AVX1-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
-; AVX1-NEXT: vpxor %xmm1, %xmm1, %xmm1
-; AVX1-NEXT: vpblendvb %xmm3, %xmm1, %xmm0, %xmm0
+; AVX1-NEXT: vpandn %xmm0, %xmm3, %xmm0
; AVX1-NEXT: vmovdqu %xmm0, (%rdi)
; AVX1-NEXT: vzeroupper
; AVX1-NEXT: retq
@@ -625,13 +622,10 @@ define void @test13(i16* nocapture %head
; AVX2-NEXT: vpcmpgtd %ymm3, %ymm2, %ymm2
; AVX2-NEXT: vextracti128 $1, %ymm2, %xmm3
; AVX2-NEXT: vpacksswb %xmm3, %xmm2, %xmm2
-; AVX2-NEXT: vpsllw $15, %xmm2, %xmm2
-; AVX2-NEXT: vpsraw $15, %xmm2, %xmm2
; AVX2-NEXT: vpsubd %ymm0, %ymm1, %ymm0
; AVX2-NEXT: vpshufb {{.*#+}} ymm0 = ymm0[0,1,4,5,8,9,12,13],zero,zero,zero,zero,zero,zero,zero,zero,ymm0[16,17,20,21,24,25,28,29],zero,zero,zero,zero,zero,zero,zero,zero
; AVX2-NEXT: vpermq {{.*#+}} ymm0 = ymm0[0,2,2,3]
-; AVX2-NEXT: vpxor %xmm1, %xmm1, %xmm1
-; AVX2-NEXT: vpblendvb %xmm2, %xmm1, %xmm0, %xmm0
+; AVX2-NEXT: vpandn %xmm0, %xmm2, %xmm0
; AVX2-NEXT: vmovdqu %xmm0, (%rdi)
; AVX2-NEXT: vzeroupper
; AVX2-NEXT: retq
@@ -984,8 +978,6 @@ define void @test15(i16* nocapture %head
; AVX1-NEXT: vxorps %xmm3, %xmm0, %xmm3
; AVX1-NEXT: vpcmpgtd %xmm3, %xmm6, %xmm3
; AVX1-NEXT: vpacksswb %xmm4, %xmm3, %xmm3
-; AVX1-NEXT: vpsllw $15, %xmm3, %xmm3
-; AVX1-NEXT: vpsraw $15, %xmm3, %xmm3
; AVX1-NEXT: vpsubd %xmm0, %xmm1, %xmm0
; AVX1-NEXT: vpsubd %xmm5, %xmm2, %xmm1
; AVX1-NEXT: vmovdqa {{.*#+}} xmm2 = [0,1,4,5,8,9,12,13,8,9,12,13,12,13,14,15]
@@ -1007,8 +999,6 @@ define void @test15(i16* nocapture %head
; AVX2-NEXT: vpcmpgtd %ymm3, %ymm2, %ymm2
; AVX2-NEXT: vextracti128 $1, %ymm2, %xmm3
; AVX2-NEXT: vpacksswb %xmm3, %xmm2, %xmm2
-; AVX2-NEXT: vpsllw $15, %xmm2, %xmm2
-; AVX2-NEXT: vpsraw $15, %xmm2, %xmm2
; AVX2-NEXT: vpsubd %ymm0, %ymm1, %ymm0
; AVX2-NEXT: vpshufb {{.*#+}} ymm0 = ymm0[0,1,4,5,8,9,12,13],zero,zero,zero,zero,zero,zero,zero,zero,ymm0[16,17,20,21,24,25,28,29],zero,zero,zero,zero,zero,zero,zero,zero
; AVX2-NEXT: vpermq {{.*#+}} ymm0 = ymm0[0,2,2,3]
@@ -1118,8 +1108,6 @@ define void @test16(i16* nocapture %head
; AVX1-NEXT: vxorps %xmm3, %xmm0, %xmm3
; AVX1-NEXT: vpcmpgtd %xmm3, %xmm6, %xmm3
; AVX1-NEXT: vpacksswb %xmm4, %xmm3, %xmm3
-; AVX1-NEXT: vpsllw $15, %xmm3, %xmm3
-; AVX1-NEXT: vpsraw $15, %xmm3, %xmm3
; AVX1-NEXT: vpsubd %xmm0, %xmm1, %xmm0
; AVX1-NEXT: vpsubd %xmm5, %xmm2, %xmm1
; AVX1-NEXT: vmovdqa {{.*#+}} xmm2 = [0,1,4,5,8,9,12,13,8,9,12,13,12,13,14,15]
@@ -1141,8 +1129,6 @@ define void @test16(i16* nocapture %head
; AVX2-NEXT: vpcmpgtd %ymm3, %ymm2, %ymm2
; AVX2-NEXT: vextracti128 $1, %ymm2, %xmm3
; AVX2-NEXT: vpacksswb %xmm3, %xmm2, %xmm2
-; AVX2-NEXT: vpsllw $15, %xmm2, %xmm2
-; AVX2-NEXT: vpsraw $15, %xmm2, %xmm2
; AVX2-NEXT: vpsubd %ymm0, %ymm1, %ymm0
; AVX2-NEXT: vpshufb {{.*#+}} ymm0 = ymm0[0,1,4,5,8,9,12,13],zero,zero,zero,zero,zero,zero,zero,zero,ymm0[16,17,20,21,24,25,28,29],zero,zero,zero,zero,zero,zero,zero,zero
; AVX2-NEXT: vpermq {{.*#+}} ymm0 = ymm0[0,2,2,3]
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