strength reduction improvement (#559)

p4lang · May 4, 2017 · 55ae691 · 55ae691
1 parent e6141c4
commit 55ae691
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Showing 15 changed files with 111 additions and 11 deletions.
diff --git a/frontends/p4/strengthReduction.cpp b/frontends/p4/strengthReduction.cpp
@@ -64,11 +64,21 @@ int StrengthReduction::isPowerOf2(const IR::Expression* expr) const {
 
 /// @section Visitor Methods
 
+const IR::Node* StrengthReduction::postorder(IR::Cmpl* expr) {
+    if (auto a = expr->expr->to<IR::Cmpl>())
+        return a->expr;
+    return expr;
+}
+
 const IR::Node* StrengthReduction::postorder(IR::BAnd* expr) {
     if (isZero(expr->left))
         return expr->left;
     if (isZero(expr->right))
         return expr->right;
+    auto l = expr->left->to<IR::Cmpl>();
+    auto r = expr->right->to<IR::Cmpl>();
+    if (l && r)
+        return new IR::Cmpl(new IR::BOr(expr->srcInfo, l->expr, r->expr));
     return expr;
 }
 
@@ -77,6 +87,10 @@ const IR::Node* StrengthReduction::postorder(IR::BOr* expr) {
         return expr->right;
     if (isZero(expr->right))
         return expr->left;
+    auto l = expr->left->to<IR::Cmpl>();
+    auto r = expr->right->to<IR::Cmpl>();
+    if (l && r)
+        return new IR::Cmpl(new IR::BAnd(expr->srcInfo, l->expr, r->expr));
     return expr;
 }
 
@@ -85,6 +99,15 @@ const IR::Node* StrengthReduction::postorder(IR::BXor* expr) {
         return expr->right;
     if (isZero(expr->right))
         return expr->left;
+    bool cmpl = false;
+    if (auto l = expr->left->to<IR::Cmpl>()) {
+        expr->left = l->expr;
+        cmpl = !cmpl; }
+    if (auto r = expr->right->to<IR::Cmpl>()) {
+        expr->right = r->expr;
+        cmpl = !cmpl; }
+    if (cmpl)
+        return new IR::Cmpl(expr);
     return expr;
 }
 
@@ -110,6 +133,22 @@ const IR::Node* StrengthReduction::postorder(IR::LOr* expr) {
     return expr;
 }
 
+const IR::Node* StrengthReduction::postorder(IR::LNot* expr) {
+    if (auto e = expr->expr->to<IR::Equ>())
+        return new IR::Neq(e->left, e->right);
+    if (auto e = expr->expr->to<IR::Neq>())
+        return new IR::Equ(e->left, e->right);
+    if (auto e = expr->expr->to<IR::Leq>())
+        return new IR::Grt(e->left, e->right);
+    if (auto e = expr->expr->to<IR::Geq>())
+        return new IR::Lss(e->left, e->right);
+    if (auto e = expr->expr->to<IR::Lss>())
+        return new IR::Geq(e->left, e->right);
+    if (auto e = expr->expr->to<IR::Grt>())
+        return new IR::Leq(e->left, e->right);
+    return expr;
+}
+
 const IR::Node* StrengthReduction::postorder(IR::Sub* expr) {
     if (isZero(expr->right))
         return expr->left;

diff --git a/frontends/p4/strengthReduction.h b/frontends/p4/strengthReduction.h
@@ -64,11 +64,13 @@ class StrengthReduction final : public Transform {
 
     using Transform::postorder;
 
+    const IR::Node* postorder(IR::Cmpl* expr) override;
     const IR::Node* postorder(IR::BAnd* expr) override;
     const IR::Node* postorder(IR::BOr* expr) override;
     const IR::Node* postorder(IR::BXor* expr) override;
     const IR::Node* postorder(IR::LAnd* expr) override;
     const IR::Node* postorder(IR::LOr* expr) override;
+    const IR::Node* postorder(IR::LNot* expr) override;
     const IR::Node* postorder(IR::Sub* expr) override;
     const IR::Node* postorder(IR::Add* expr) override;
     const IR::Node* postorder(IR::Shl* expr) override;

diff --git a/testdata/p4_14_samples_outputs/checksum-midend.p4 b/testdata/p4_14_samples_outputs/checksum-midend.p4
@@ -90,7 +90,7 @@ control verifyChecksum(in headers hdr, inout metadata meta) {
     bit<16> tmp_4;
     @name("ipv4_checksum") Checksum16() ipv4_checksum;
     apply {
-        if (!(hdr.ipv4.ihl == 4w5)) 
+        if (hdr.ipv4.ihl != 4w5) 
             tmp_3 = false;
         else {
             tmp_4 = ipv4_checksum.get<tuple_0>({ hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr });

diff --git a/testdata/p4_14_samples_outputs/parser_dc_full-midend.p4 b/testdata/p4_14_samples_outputs/parser_dc_full-midend.p4
@@ -710,7 +710,7 @@ control verifyChecksum(in headers hdr, inout metadata meta) {
         }
         if (tmp_11) 
             mark_to_drop();
-        if (!(hdr.ipv4.ihl == 4w5)) 
+        if (hdr.ipv4.ihl != 4w5) 
             tmp_14 = false;
         else {
             tmp_15 = ipv4_checksum.get<tuple_0>({ hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr });

diff --git a/testdata/p4_14_samples_outputs/port_vlan_mapping-midend.p4 b/testdata/p4_14_samples_outputs/port_vlan_mapping-midend.p4
@@ -934,7 +934,7 @@ control verifyChecksum(in headers hdr, inout metadata meta) {
         }
         if (tmp_11) 
             mark_to_drop();
-        if (!(hdr.ipv4.ihl == 4w5)) 
+        if (hdr.ipv4.ihl != 4w5) 
             tmp_14 = false;
         else {
             tmp_15 = ipv4_checksum.get<tuple_0>({ hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr });

diff --git a/testdata/p4_14_samples_outputs/sai_p4-midend.p4 b/testdata/p4_14_samples_outputs/sai_p4-midend.p4
@@ -382,7 +382,7 @@ control verifyChecksum(in headers hdr, inout metadata meta) {
     bit<16> tmp_4;
     @name("ipv4_checksum") Checksum16() ipv4_checksum;
     apply {
-        if (!(hdr.ipv4.ihl == 4w5)) 
+        if (hdr.ipv4.ihl != 4w5) 
             tmp_3 = false;
         else {
             tmp_4 = ipv4_checksum.get<tuple_0>({ hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.ipv4_length, hdr.ipv4.id, hdr.ipv4.flags, hdr.ipv4.offset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr });

diff --git a/testdata/p4_14_samples_outputs/switch_20160226/switch-midend.p4 b/testdata/p4_14_samples_outputs/switch_20160226/switch-midend.p4
@@ -5050,15 +5050,15 @@ control verifyChecksum(in headers hdr, inout metadata meta) {
     @name("inner_ipv4_checksum") Checksum16() inner_ipv4_checksum;
     @name("ipv4_checksum") Checksum16() ipv4_checksum;
     apply {
-        if (!(hdr.inner_ipv4.ihl == 4w5)) 
+        if (hdr.inner_ipv4.ihl != 4w5) 
             tmp_1 = false;
         else {
             tmp_2 = inner_ipv4_checksum.get<tuple_8>({ hdr.inner_ipv4.version, hdr.inner_ipv4.ihl, hdr.inner_ipv4.diffserv, hdr.inner_ipv4.totalLen, hdr.inner_ipv4.identification, hdr.inner_ipv4.flags, hdr.inner_ipv4.fragOffset, hdr.inner_ipv4.ttl, hdr.inner_ipv4.protocol, hdr.inner_ipv4.srcAddr, hdr.inner_ipv4.dstAddr });
             tmp_1 = hdr.inner_ipv4.hdrChecksum == tmp_2;
         }
         if (tmp_1) 
             mark_to_drop();
-        if (!(hdr.ipv4.ihl == 4w5)) 
+        if (hdr.ipv4.ihl != 4w5) 
             tmp_4 = false;
         else {
             tmp_5 = ipv4_checksum.get<tuple_8>({ hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr });

diff --git a/testdata/p4_14_samples_outputs/switch_20160512/switch-first.p4 b/testdata/p4_14_samples_outputs/switch_20160512/switch-first.p4
@@ -5576,7 +5576,7 @@ control process_fwd_results(inout headers hdr, inout metadata meta, inout standa
         default_action = NoAction();
     }
     apply {
-        if (!(meta.ingress_metadata.bypass_lookups == 16w0xffff)) 
+        if (meta.ingress_metadata.bypass_lookups != 16w0xffff) 
             fwd_result.apply();
     }
 }

diff --git a/testdata/p4_14_samples_outputs/switch_20160512/switch-frontend.p4 b/testdata/p4_14_samples_outputs/switch_20160512/switch-frontend.p4
@@ -5456,7 +5456,7 @@ control process_fwd_results(inout headers hdr, inout metadata meta, inout standa
         default_action = NoAction();
     }
     apply {
-        if (!(meta.ingress_metadata.bypass_lookups == 16w0xffff)) 
+        if (meta.ingress_metadata.bypass_lookups != 16w0xffff) 
             fwd_result_0.apply();
     }
 }

diff --git a/testdata/p4_14_samples_outputs/switch_20160512/switch-midend.p4 b/testdata/p4_14_samples_outputs/switch_20160512/switch-midend.p4
@@ -5948,7 +5948,7 @@ control ingress(inout headers hdr, inout metadata meta, inout standard_metadata_
             process_ingress_bd_stats_ingress_bd_stats_0.apply();
             process_ingress_acl_stats_acl_stats_0.apply();
             process_storm_control_stats_storm_control_stats_2.apply();
-            if (!(meta.ingress_metadata.bypass_lookups == 16w0xffff)) 
+            if (meta.ingress_metadata.bypass_lookups != 16w0xffff) 
                 process_fwd_results_fwd_result_0.apply();
             if (meta.nexthop_metadata.nexthop_type == 1w1) 
                 process_nexthop_ecmp_group_0.apply();
@@ -6042,15 +6042,15 @@ control verifyChecksum(in headers hdr, inout metadata meta) {
     @name("inner_ipv4_checksum") Checksum16() inner_ipv4_checksum;
     @name("ipv4_checksum") Checksum16() ipv4_checksum;
     apply {
-        if (!(hdr.inner_ipv4.ihl == 4w5)) 
+        if (hdr.inner_ipv4.ihl != 4w5) 
             tmp_1 = false;
         else {
             tmp_2 = inner_ipv4_checksum.get<tuple_10>({ hdr.inner_ipv4.version, hdr.inner_ipv4.ihl, hdr.inner_ipv4.diffserv, hdr.inner_ipv4.totalLen, hdr.inner_ipv4.identification, hdr.inner_ipv4.flags, hdr.inner_ipv4.fragOffset, hdr.inner_ipv4.ttl, hdr.inner_ipv4.protocol, hdr.inner_ipv4.srcAddr, hdr.inner_ipv4.dstAddr });
             tmp_1 = hdr.inner_ipv4.hdrChecksum == tmp_2;
         }
         if (tmp_1) 
             mark_to_drop();
-        if (!(hdr.ipv4.ihl == 4w5)) 
+        if (hdr.ipv4.ihl != 4w5) 
             tmp_4 = false;
         else {
             tmp_5 = ipv4_checksum.get<tuple_10>({ hdr.ipv4.version, hdr.ipv4.ihl, hdr.ipv4.diffserv, hdr.ipv4.totalLen, hdr.ipv4.identification, hdr.ipv4.flags, hdr.ipv4.fragOffset, hdr.ipv4.ttl, hdr.ipv4.protocol, hdr.ipv4.srcAddr, hdr.ipv4.dstAddr });

diff --git a/testdata/p4_16_samples/strength2.p4 b/testdata/p4_16_samples/strength2.p4
@@ -0,0 +1,30 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc. 
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+control strength() {
+    apply {
+        bit<4> x;
+        bit<4> y;
+        bit<4> z;
+        z = ~x ^ ~y;
+        if (!(x < y)) {
+            z = ~(x ^ (~y & ~z));
+        }
+        if (!(x > y)) {
+            z = ~(x ^ (~y | ~z));
+        }
+    }
+}
diff --git a/testdata/p4_16_samples_outputs/strength2-first.p4 b/testdata/p4_16_samples_outputs/strength2-first.p4
@@ -0,0 +1,13 @@
+control strength() {
+    apply {
+        bit<4> x;
+        bit<4> y;
+        bit<4> z;
+        z = x ^ y;
+        if (x >= y) 
+            z = x ^ (y | z);
+        if (x <= y) 
+            z = x ^ y & z;
+    }
+}
+
diff --git a/testdata/p4_16_samples_outputs/strength2-frontend.p4 b/testdata/p4_16_samples_outputs/strength2-frontend.p4
diff --git a/testdata/p4_16_samples_outputs/strength2.p4 b/testdata/p4_16_samples_outputs/strength2.p4
@@ -0,0 +1,15 @@
+control strength() {
+    apply {
+        bit<4> x;
+        bit<4> y;
+        bit<4> z;
+        z = ~x ^ ~y;
+        if (!(x < y)) {
+            z = ~(x ^ ~y & ~z);
+        }
+        if (!(x > y)) {
+            z = ~(x ^ (~y | ~z));
+        }
+    }
+}
+
diff --git a/testdata/p4_16_samples_outputs/strength2.p4-stderr b/testdata/p4_16_samples_outputs/strength2.p4-stderr
@@ -0,0 +1 @@
+warning: Program does not contain a `main' module