[llvm] r351070 - [DAGCombiner] Add add/sub saturation undef handling
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Mon Jan 14 06:16:24 PST 2019
Author: rksimon
Date: Mon Jan 14 06:16:24 2019
New Revision: 351070
URL: http://llvm.org/viewvc/llvm-project?rev=351070&view=rev
Log:
[DAGCombiner] Add add/sub saturation undef handling
Match ConstantFolding.cpp:
(add_sat x, undef) -> -1
(sub_sat x, undef) -> 0
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/trunk/test/CodeGen/X86/combine-add-ssat.ll
llvm/trunk/test/CodeGen/X86/combine-add-usat.ll
llvm/trunk/test/CodeGen/X86/combine-sub-ssat.ll
llvm/trunk/test/CodeGen/X86/combine-sub-usat.ll
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=351070&r1=351069&r2=351070&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Jan 14 06:16:24 2019
@@ -2194,6 +2194,10 @@ SDValue DAGCombiner::visitADDSAT(SDNode
return N1;
}
+ // fold (add_sat x, undef) -> -1
+ if (N0.isUndef() || N1.isUndef())
+ return DAG.getAllOnesConstant(DL, VT);
+
if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) {
// canonicalize constant to RHS
if (!DAG.isConstantIntBuildVectorOrConstantInt(N1))
@@ -2792,6 +2796,10 @@ SDValue DAGCombiner::visitSUBSAT(SDNode
return N0;
}
+ // fold (sub_sat x, undef) -> 0
+ if (N0.isUndef() || N1.isUndef())
+ return DAG.getConstant(0, DL, VT);
+
// TODO Constant Folding
// fold (sub_sat x, 0) -> x
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=351070&r1=351069&r2=351070&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Jan 14 06:16:24 2019
@@ -5180,6 +5180,8 @@ SDValue SelectionDAG::getNode(unsigned O
case ISD::SDIV:
case ISD::UREM:
case ISD::SREM:
+ case ISD::SSUBSAT:
+ case ISD::USUBSAT:
return getConstant(0, DL, VT); // fold op(undef, arg2) -> 0
}
}
@@ -5203,8 +5205,12 @@ SDValue SelectionDAG::getNode(unsigned O
return getUNDEF(VT); // fold op(arg1, undef) -> undef
case ISD::MUL:
case ISD::AND:
+ case ISD::SSUBSAT:
+ case ISD::USUBSAT:
return getConstant(0, DL, VT); // fold op(arg1, undef) -> 0
case ISD::OR:
+ case ISD::SADDSAT:
+ case ISD::UADDSAT:
return getAllOnesConstant(DL, VT);
}
}
Modified: llvm/trunk/test/CodeGen/X86/combine-add-ssat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/combine-add-ssat.ll?rev=351070&r1=351069&r2=351070&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/combine-add-ssat.ll (original)
+++ llvm/trunk/test/CodeGen/X86/combine-add-ssat.ll Mon Jan 14 06:16:24 2019
@@ -15,13 +15,7 @@ declare <8 x i16> @llvm.sadd.sat.v8i16(
define i32 @combine_undef_i32(i32 %a0) {
; CHECK-LABEL: combine_undef_i32:
; CHECK: # %bb.0:
-; CHECK-NEXT: xorl %eax, %eax
-; CHECK-NEXT: movl %edi, %ecx
-; CHECK-NEXT: addl %eax, %ecx
-; CHECK-NEXT: setns %al
-; CHECK-NEXT: addl $2147483647, %eax # imm = 0x7FFFFFFF
-; CHECK-NEXT: addl %eax, %edi
-; CHECK-NEXT: cmovnol %edi, %eax
+; CHECK-NEXT: movl $-1, %eax
; CHECK-NEXT: retq
%res = call i32 @llvm.sadd.sat.i32(i32 %a0, i32 undef)
ret i32 %res
@@ -30,12 +24,12 @@ define i32 @combine_undef_i32(i32 %a0) {
define <8 x i16> @combine_undef_v8i16(<8 x i16> %a0) {
; SSE-LABEL: combine_undef_v8i16:
; SSE: # %bb.0:
-; SSE-NEXT: paddsw %xmm0, %xmm0
+; SSE-NEXT: pcmpeqd %xmm0, %xmm0
; SSE-NEXT: retq
;
; AVX-LABEL: combine_undef_v8i16:
; AVX: # %bb.0:
-; AVX-NEXT: vpaddsw %xmm0, %xmm0, %xmm0
+; AVX-NEXT: vpcmpeqd %xmm0, %xmm0, %xmm0
; AVX-NEXT: retq
%res = call <8 x i16> @llvm.sadd.sat.v8i16(<8 x i16> undef, <8 x i16> %a0)
ret <8 x i16> %res
@@ -68,14 +62,12 @@ define <8 x i16> @combine_constfold_v8i1
define <8 x i16> @combine_constfold_undef_v8i16() {
; SSE-LABEL: combine_constfold_undef_v8i16:
; SSE: # %bb.0:
-; SSE-NEXT: movdqa {{.*#+}} xmm0 = <u,1,u,65535,65535,65281,32776,1>
-; SSE-NEXT: paddsw {{.*}}(%rip), %xmm0
+; SSE-NEXT: movaps {{.*#+}} xmm0 = [65535,65535,65535,65534,0,65280,32768,0]
; SSE-NEXT: retq
;
; AVX-LABEL: combine_constfold_undef_v8i16:
; AVX: # %bb.0:
-; AVX-NEXT: vmovdqa {{.*#+}} xmm0 = <u,1,u,65535,65535,65281,32776,1>
-; AVX-NEXT: vpaddsw {{.*}}(%rip), %xmm0, %xmm0
+; AVX-NEXT: vmovaps {{.*#+}} xmm0 = [65535,65535,65535,65534,0,65280,32768,0]
; AVX-NEXT: retq
%res = call <8 x i16> @llvm.sadd.sat.v8i16(<8 x i16> <i16 undef, i16 1, i16 undef, i16 65535, i16 -1, i16 -255, i16 -32760, i16 1>, <8 x i16> <i16 1, i16 undef, i16 undef, i16 65535, i16 1, i16 65535, i16 -10, i16 65535>)
ret <8 x i16> %res
Modified: llvm/trunk/test/CodeGen/X86/combine-add-usat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/combine-add-usat.ll?rev=351070&r1=351069&r2=351070&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/combine-add-usat.ll (original)
+++ llvm/trunk/test/CodeGen/X86/combine-add-usat.ll Mon Jan 14 06:16:24 2019
@@ -15,9 +15,7 @@ declare <8 x i16> @llvm.uadd.sat.v8i16(
define i32 @combine_undef_i32(i32 %a0) {
; CHECK-LABEL: combine_undef_i32:
; CHECK: # %bb.0:
-; CHECK-NEXT: addl %eax, %edi
; CHECK-NEXT: movl $-1, %eax
-; CHECK-NEXT: cmovael %edi, %eax
; CHECK-NEXT: retq
%res = call i32 @llvm.uadd.sat.i32(i32 %a0, i32 undef)
ret i32 %res
@@ -26,12 +24,12 @@ define i32 @combine_undef_i32(i32 %a0) {
define <8 x i16> @combine_undef_v8i16(<8 x i16> %a0) {
; SSE-LABEL: combine_undef_v8i16:
; SSE: # %bb.0:
-; SSE-NEXT: paddusw %xmm0, %xmm0
+; SSE-NEXT: pcmpeqd %xmm0, %xmm0
; SSE-NEXT: retq
;
; AVX-LABEL: combine_undef_v8i16:
; AVX: # %bb.0:
-; AVX-NEXT: vpaddusw %xmm0, %xmm0, %xmm0
+; AVX-NEXT: vpcmpeqd %xmm0, %xmm0, %xmm0
; AVX-NEXT: retq
%res = call <8 x i16> @llvm.uadd.sat.v8i16(<8 x i16> undef, <8 x i16> %a0)
ret <8 x i16> %res
@@ -64,14 +62,12 @@ define <8 x i16> @combine_constfold_v8i1
define <8 x i16> @combine_constfold_undef_v8i16() {
; SSE-LABEL: combine_constfold_undef_v8i16:
; SSE: # %bb.0:
-; SSE-NEXT: movdqa {{.*#+}} xmm0 = <u,1,u,65535,65535,65281,1,1>
-; SSE-NEXT: paddusw {{.*}}(%rip), %xmm0
+; SSE-NEXT: movaps {{.*#+}} xmm0 = [65535,65535,65535,65535,65535,65535,2,65535]
; SSE-NEXT: retq
;
; AVX-LABEL: combine_constfold_undef_v8i16:
; AVX: # %bb.0:
-; AVX-NEXT: vmovdqa {{.*#+}} xmm0 = <u,1,u,65535,65535,65281,1,1>
-; AVX-NEXT: vpaddusw {{.*}}(%rip), %xmm0, %xmm0
+; AVX-NEXT: vmovaps {{.*#+}} xmm0 = [65535,65535,65535,65535,65535,65535,2,65535]
; AVX-NEXT: retq
%res = call <8 x i16> @llvm.uadd.sat.v8i16(<8 x i16> <i16 undef, i16 1, i16 undef, i16 65535, i16 -1, i16 -255, i16 -65535, i16 1>, <8 x i16> <i16 1, i16 undef, i16 undef, i16 65535, i16 1, i16 65535, i16 1, i16 65535>)
ret <8 x i16> %res
Modified: llvm/trunk/test/CodeGen/X86/combine-sub-ssat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/combine-sub-ssat.ll?rev=351070&r1=351069&r2=351070&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/combine-sub-ssat.ll (original)
+++ llvm/trunk/test/CodeGen/X86/combine-sub-ssat.ll Mon Jan 14 06:16:24 2019
@@ -16,12 +16,6 @@ define i32 @combine_undef_i32(i32 %a0) {
; CHECK-LABEL: combine_undef_i32:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
-; CHECK-NEXT: movl %edi, %ecx
-; CHECK-NEXT: subl %eax, %ecx
-; CHECK-NEXT: setns %al
-; CHECK-NEXT: addl $2147483647, %eax # imm = 0x7FFFFFFF
-; CHECK-NEXT: subl %eax, %edi
-; CHECK-NEXT: cmovnol %edi, %eax
; CHECK-NEXT: retq
%res = call i32 @llvm.ssub.sat.i32(i32 %a0, i32 undef)
ret i32 %res
@@ -30,12 +24,12 @@ define i32 @combine_undef_i32(i32 %a0) {
define <8 x i16> @combine_undef_v8i16(<8 x i16> %a0) {
; SSE-LABEL: combine_undef_v8i16:
; SSE: # %bb.0:
-; SSE-NEXT: psubsw %xmm0, %xmm0
+; SSE-NEXT: xorps %xmm0, %xmm0
; SSE-NEXT: retq
;
; AVX-LABEL: combine_undef_v8i16:
; AVX: # %bb.0:
-; AVX-NEXT: vpsubsw %xmm0, %xmm0, %xmm0
+; AVX-NEXT: vxorps %xmm0, %xmm0, %xmm0
; AVX-NEXT: retq
%res = call <8 x i16> @llvm.ssub.sat.v8i16(<8 x i16> undef, <8 x i16> %a0)
ret <8 x i16> %res
Modified: llvm/trunk/test/CodeGen/X86/combine-sub-usat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/combine-sub-usat.ll?rev=351070&r1=351069&r2=351070&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/combine-sub-usat.ll (original)
+++ llvm/trunk/test/CodeGen/X86/combine-sub-usat.ll Mon Jan 14 06:16:24 2019
@@ -16,8 +16,6 @@ define i32 @combine_undef_i32(i32 %a0) {
; CHECK-LABEL: combine_undef_i32:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
-; CHECK-NEXT: subl %eax, %edi
-; CHECK-NEXT: cmovael %edi, %eax
; CHECK-NEXT: retq
%res = call i32 @llvm.usub.sat.i32(i32 %a0, i32 undef)
ret i32 %res
@@ -26,12 +24,12 @@ define i32 @combine_undef_i32(i32 %a0) {
define <8 x i16> @combine_undef_v8i16(<8 x i16> %a0) {
; SSE-LABEL: combine_undef_v8i16:
; SSE: # %bb.0:
-; SSE-NEXT: psubusw %xmm0, %xmm0
+; SSE-NEXT: xorps %xmm0, %xmm0
; SSE-NEXT: retq
;
; AVX-LABEL: combine_undef_v8i16:
; AVX: # %bb.0:
-; AVX-NEXT: vpsubusw %xmm0, %xmm0, %xmm0
+; AVX-NEXT: vxorps %xmm0, %xmm0, %xmm0
; AVX-NEXT: retq
%res = call <8 x i16> @llvm.usub.sat.v8i16(<8 x i16> undef, <8 x i16> %a0)
ret <8 x i16> %res
More information about the llvm-commits
mailing list