[llvm] [clang-tools-extra] [PowerPC] Combine sub within setcc back to sext (PR #66978)
Qiu Chaofan via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 16 00:50:28 PST 2023
https://github.com/ecnelises updated https://github.com/llvm/llvm-project/pull/66978
>From 2a7b9be6cd0705590c85c51b35ea99fe053aaf47 Mon Sep 17 00:00:00 2001
From: Qiu Chaofan <qiucofan at cn.ibm.com>
Date: Wed, 6 Sep 2023 16:16:34 +0800
Subject: [PATCH 1/2] [PowerPC] Combine sub within setcc back to sext
---
llvm/lib/Target/PowerPC/PPCISelLowering.cpp | 37 +++++++++++++-----
llvm/test/CodeGen/PowerPC/setcc-to-sub.ll | 42 +++++++++++++++++++++
2 files changed, 69 insertions(+), 10 deletions(-)
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index f4e3531980d165f..4659ebef35ecf62 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -14407,15 +14407,18 @@ SDValue PPCTargetLowering::DAGCombineExtBoolTrunc(SDNode *N,
ShiftCst);
}
-SDValue PPCTargetLowering::combineSetCC(SDNode *N,
- DAGCombinerInfo &DCI) const {
- assert(N->getOpcode() == ISD::SETCC &&
- "Should be called with a SETCC node");
+SDValue PPCTargetLowering::combineSetCC(SDNode *N, DAGCombinerInfo &DCI) const {
+ assert(N->getOpcode() == ISD::SETCC && "Should be called with a SETCC node");
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(2))->get();
+ SDValue LHS = N->getOperand(0);
+ SDValue RHS = N->getOperand(1);
+ SDLoc DL(N);
+ SelectionDAG &DAG = DCI.DAG;
+ EVT VT = N->getValueType(0);
+ EVT OpVT = LHS.getValueType();
+
if (CC == ISD::SETNE || CC == ISD::SETEQ) {
- SDValue LHS = N->getOperand(0);
- SDValue RHS = N->getOperand(1);
// If there is a '0 - y' pattern, canonicalize the pattern to the RHS.
if (LHS.getOpcode() == ISD::SUB && isNullConstant(LHS.getOperand(0)) &&
@@ -14426,15 +14429,29 @@ SDValue PPCTargetLowering::combineSetCC(SDNode *N,
// x != 0-y --> x+y != 0
if (RHS.getOpcode() == ISD::SUB && isNullConstant(RHS.getOperand(0)) &&
RHS.hasOneUse()) {
- SDLoc DL(N);
- SelectionDAG &DAG = DCI.DAG;
- EVT VT = N->getValueType(0);
- EVT OpVT = LHS.getValueType();
SDValue Add = DAG.getNode(ISD::ADD, DL, OpVT, LHS, RHS.getOperand(1));
return DAG.getSetCC(DL, VT, Add, DAG.getConstant(0, DL, OpVT), CC);
}
}
+ // Combine (a-2^(M-1)) => sext(trunc(a, M), 64)
+ if (CC == ISD::SETULT && LHS.getOpcode() == ISD::ADD && OpVT == MVT::i64 &&
+ isa<ConstantSDNode>(RHS) && isa<ConstantSDNode>(LHS.getOperand(1))) {
+ uint64_t ShiftVal =
+ ~(cast<ConstantSDNode>(LHS.getOperand(1))->getZExtValue()) + 1;
+ uint64_t CmpVal = ~(cast<ConstantSDNode>(RHS)->getZExtValue()) + 1;
+ if (isPowerOf2_64(ShiftVal) && ShiftVal << 1 == CmpVal) {
+ unsigned DestBits = Log2_64(CmpVal);
+ if (DestBits == 8 || DestBits == 16 || DestBits == 32) {
+ SDValue Conv =
+ DAG.getSExtOrTrunc(DAG.getSExtOrTrunc(LHS.getOperand(0), DL,
+ MVT::getIntegerVT(DestBits)),
+ DL, OpVT);
+ return DAG.getSetCC(DL, VT, LHS.getOperand(0), Conv, ISD::SETNE);
+ }
+ }
+ }
+
return DAGCombineTruncBoolExt(N, DCI);
}
diff --git a/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll b/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll
index 13c629b6349450c..ce75b77eed29666 100644
--- a/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll
+++ b/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll
@@ -89,6 +89,48 @@ entry:
ret i1 %cmp.i5
}
+define zeroext i1 @test5(i64 %a) {
+; CHECK-LABEL: test5:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: extsw 4, 3
+; CHECK-NEXT: xor 3, 3, 4
+; CHECK-NEXT: addic 4, 3, -1
+; CHECK-NEXT: subfe 3, 4, 3
+; CHECK-NEXT: blr
+entry:
+ %0 = add i64 %a, -2147483648
+ %cmp = icmp ult i64 %0, -4294967296
+ ret i1 %cmp
+}
+
+define zeroext i1 @test6(i64 %a) {
+; CHECK-LABEL: test6:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: extsh 4, 3
+; CHECK-NEXT: xor 3, 3, 4
+; CHECK-NEXT: addic 4, 3, -1
+; CHECK-NEXT: subfe 3, 4, 3
+; CHECK-NEXT: blr
+entry:
+ %0 = add i64 %a, -32768
+ %cmp = icmp ult i64 %0, -65536
+ ret i1 %cmp
+}
+
+define zeroext i1 @test7(i64 %a) {
+; CHECK-LABEL: test7:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: extsb 4, 3
+; CHECK-NEXT: xor 3, 3, 4
+; CHECK-NEXT: addic 4, 3, -1
+; CHECK-NEXT: subfe 3, 4, 3
+; CHECK-NEXT: blr
+entry:
+ %0 = add i64 %a, -128
+ %cmp = icmp ult i64 %0, -256
+ ret i1 %cmp
+}
+
!1 = !{!2, !2, i64 0}
!2 = !{!"int", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
>From fbb7e6362d6223f8e0ee6014e000c1cc5ae6e777 Mon Sep 17 00:00:00 2001
From: Qiu Chaofan <qiucofan at cn.ibm.com>
Date: Wed, 6 Sep 2023 16:16:34 +0800
Subject: [PATCH 2/2] [PowerPC] Combine sub within setcc back to sext
---
llvm/lib/Target/PowerPC/PPCISelLowering.cpp | 37 +++++++++++++-----
llvm/test/CodeGen/PowerPC/setcc-to-sub.ll | 42 +++++++++++++++++++++
2 files changed, 69 insertions(+), 10 deletions(-)
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index f4e3531980d165f..4659ebef35ecf62 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -14407,15 +14407,18 @@ SDValue PPCTargetLowering::DAGCombineExtBoolTrunc(SDNode *N,
ShiftCst);
}
-SDValue PPCTargetLowering::combineSetCC(SDNode *N,
- DAGCombinerInfo &DCI) const {
- assert(N->getOpcode() == ISD::SETCC &&
- "Should be called with a SETCC node");
+SDValue PPCTargetLowering::combineSetCC(SDNode *N, DAGCombinerInfo &DCI) const {
+ assert(N->getOpcode() == ISD::SETCC && "Should be called with a SETCC node");
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(2))->get();
+ SDValue LHS = N->getOperand(0);
+ SDValue RHS = N->getOperand(1);
+ SDLoc DL(N);
+ SelectionDAG &DAG = DCI.DAG;
+ EVT VT = N->getValueType(0);
+ EVT OpVT = LHS.getValueType();
+
if (CC == ISD::SETNE || CC == ISD::SETEQ) {
- SDValue LHS = N->getOperand(0);
- SDValue RHS = N->getOperand(1);
// If there is a '0 - y' pattern, canonicalize the pattern to the RHS.
if (LHS.getOpcode() == ISD::SUB && isNullConstant(LHS.getOperand(0)) &&
@@ -14426,15 +14429,29 @@ SDValue PPCTargetLowering::combineSetCC(SDNode *N,
// x != 0-y --> x+y != 0
if (RHS.getOpcode() == ISD::SUB && isNullConstant(RHS.getOperand(0)) &&
RHS.hasOneUse()) {
- SDLoc DL(N);
- SelectionDAG &DAG = DCI.DAG;
- EVT VT = N->getValueType(0);
- EVT OpVT = LHS.getValueType();
SDValue Add = DAG.getNode(ISD::ADD, DL, OpVT, LHS, RHS.getOperand(1));
return DAG.getSetCC(DL, VT, Add, DAG.getConstant(0, DL, OpVT), CC);
}
}
+ // Combine (a-2^(M-1)) => sext(trunc(a, M), 64)
+ if (CC == ISD::SETULT && LHS.getOpcode() == ISD::ADD && OpVT == MVT::i64 &&
+ isa<ConstantSDNode>(RHS) && isa<ConstantSDNode>(LHS.getOperand(1))) {
+ uint64_t ShiftVal =
+ ~(cast<ConstantSDNode>(LHS.getOperand(1))->getZExtValue()) + 1;
+ uint64_t CmpVal = ~(cast<ConstantSDNode>(RHS)->getZExtValue()) + 1;
+ if (isPowerOf2_64(ShiftVal) && ShiftVal << 1 == CmpVal) {
+ unsigned DestBits = Log2_64(CmpVal);
+ if (DestBits == 8 || DestBits == 16 || DestBits == 32) {
+ SDValue Conv =
+ DAG.getSExtOrTrunc(DAG.getSExtOrTrunc(LHS.getOperand(0), DL,
+ MVT::getIntegerVT(DestBits)),
+ DL, OpVT);
+ return DAG.getSetCC(DL, VT, LHS.getOperand(0), Conv, ISD::SETNE);
+ }
+ }
+ }
+
return DAGCombineTruncBoolExt(N, DCI);
}
diff --git a/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll b/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll
index 13c629b6349450c..ce75b77eed29666 100644
--- a/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll
+++ b/llvm/test/CodeGen/PowerPC/setcc-to-sub.ll
@@ -89,6 +89,48 @@ entry:
ret i1 %cmp.i5
}
+define zeroext i1 @test5(i64 %a) {
+; CHECK-LABEL: test5:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: extsw 4, 3
+; CHECK-NEXT: xor 3, 3, 4
+; CHECK-NEXT: addic 4, 3, -1
+; CHECK-NEXT: subfe 3, 4, 3
+; CHECK-NEXT: blr
+entry:
+ %0 = add i64 %a, -2147483648
+ %cmp = icmp ult i64 %0, -4294967296
+ ret i1 %cmp
+}
+
+define zeroext i1 @test6(i64 %a) {
+; CHECK-LABEL: test6:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: extsh 4, 3
+; CHECK-NEXT: xor 3, 3, 4
+; CHECK-NEXT: addic 4, 3, -1
+; CHECK-NEXT: subfe 3, 4, 3
+; CHECK-NEXT: blr
+entry:
+ %0 = add i64 %a, -32768
+ %cmp = icmp ult i64 %0, -65536
+ ret i1 %cmp
+}
+
+define zeroext i1 @test7(i64 %a) {
+; CHECK-LABEL: test7:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: extsb 4, 3
+; CHECK-NEXT: xor 3, 3, 4
+; CHECK-NEXT: addic 4, 3, -1
+; CHECK-NEXT: subfe 3, 4, 3
+; CHECK-NEXT: blr
+entry:
+ %0 = add i64 %a, -128
+ %cmp = icmp ult i64 %0, -256
+ ret i1 %cmp
+}
+
!1 = !{!2, !2, i64 0}
!2 = !{!"int", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
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