[llvm] [RISCV][GISel] Lower G_SCMP and G_UCMP. (PR #119112)

Craig Topper via llvm-commits llvm-commits at lists.llvm.org
Sat Dec 7 20:37:06 PST 2024 

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/119112

Codegen is not optimal for RISC-V yet. We should port the (sub (setgt X, Y), (setlt X, Y)) lowering from SelectionDAG.

>From 5036d7f8a0d0bfffc8a65e12958f72769606d1dc Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Sat, 7 Dec 2024 20:33:17 -0800
Subject: [PATCH] [RISCV][GISel] Lower G_SCMP and G_UCMP.

---
 .../Target/RISCV/GISel/RISCVLegalizerInfo.cpp |  2 +
 .../GlobalISel/legalizer-info-validation.mir  |  9 ++-
 .../legalizer/legalize-threeway-cmp-rv32.mir  | 58 ++++++++++++++
 .../legalizer/legalize-threeway-cmp-rv64.mir  | 75 +++++++++++++++++++
 4 files changed, 140 insertions(+), 4 deletions(-)
 create mode 100644 llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv32.mir
 create mode 100644 llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv64.mir

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp b/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
index 1199dabf3d1659..21bfb444a569d4 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
@@ -482,6 +482,8 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST)
       .minScalar(ST.hasStdExtZbb(), 0, sXLen)
       .lower();
 
+  getActionDefinitionsBuilder({G_SCMP, G_UCMP}).lower();
+
   getActionDefinitionsBuilder(G_FRAME_INDEX).legalFor({p0});
 
   getActionDefinitionsBuilder({G_MEMCPY, G_MEMMOVE, G_MEMSET}).libcall();
diff --git a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer-info-validation.mir b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer-info-validation.mir
index fb28a260c82718..a27e2b80cd98fb 100644
--- a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer-info-validation.mir
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer-info-validation.mir
@@ -364,11 +364,12 @@
 # DEBUG-NEXT: .. the first uncovered type index: 2, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 # DEBUG-NEXT: G_SCMP (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_UCMP (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_SELECT (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
diff --git a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv32.mir b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv32.mir
new file mode 100644
index 00000000000000..5c3d7e5975f1fd
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv32.mir
@@ -0,0 +1,58 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=riscv32 -run-pass=legalizer %s -o - | FileCheck %s
+
+---
+name:            test_ucmp_i32
+body:             |
+  bb.1:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: test_ucmp_i32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
+    ; CHECK-NEXT: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(sgt), [[COPY]](s32), [[COPY1]]
+    ; CHECK-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s32), [[C]], [[C1]]
+    ; CHECK-NEXT: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 -1
+    ; CHECK-NEXT: [[ICMP1:%[0-9]+]]:_(s32) = G_ICMP intpred(slt), [[COPY]](s32), [[COPY1]]
+    ; CHECK-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ICMP1]](s32), [[C2]], [[SELECT]]
+    ; CHECK-NEXT: $x10 = COPY [[SELECT1]](s32)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:_(s32) = COPY $x10
+    %1:_(s32) = COPY $x11
+    %2:_(s32) = G_SCMP %0(s32), %1
+    $x10 = COPY %2(s32)
+    PseudoRET implicit $x10
+
+...
+---
+name:            test_scmp_i32
+alignment:       4
+body:             |
+  bb.1:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: test_scmp_i32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
+    ; CHECK-NEXT: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(sgt), [[COPY]](s32), [[COPY1]]
+    ; CHECK-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s32), [[C]], [[C1]]
+    ; CHECK-NEXT: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 -1
+    ; CHECK-NEXT: [[ICMP1:%[0-9]+]]:_(s32) = G_ICMP intpred(slt), [[COPY]](s32), [[COPY1]]
+    ; CHECK-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ICMP1]](s32), [[C2]], [[SELECT]]
+    ; CHECK-NEXT: $x10 = COPY [[SELECT1]](s32)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:_(s32) = COPY $x10
+    %1:_(s32) = COPY $x11
+    %2:_(s32) = G_SCMP %0(s32), %1
+    $x10 = COPY %2(s32)
+    PseudoRET implicit $x10
+
+...
diff --git a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv64.mir b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv64.mir
new file mode 100644
index 00000000000000..ccade88ffae7c8
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-threeway-cmp-rv64.mir
@@ -0,0 +1,75 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=riscv64 -run-pass=legalizer %s -o - | FileCheck %s
+
+---
+name:            test_ucmp_i32
+body:             |
+  bb.1:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: test_ucmp_i32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 1
+    ; CHECK-NEXT: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[C]](s64)
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+    ; CHECK-NEXT: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[C1]](s64)
+    ; CHECK-NEXT: [[SEXT_INREG:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY]], 32
+    ; CHECK-NEXT: [[SEXT_INREG1:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY1]], 32
+    ; CHECK-NEXT: [[ICMP:%[0-9]+]]:_(s64) = G_ICMP intpred(sgt), [[SEXT_INREG]](s64), [[SEXT_INREG1]]
+    ; CHECK-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s64), [[TRUNC]], [[TRUNC1]]
+    ; CHECK-NEXT: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 -1
+    ; CHECK-NEXT: [[TRUNC2:%[0-9]+]]:_(s32) = G_TRUNC [[C2]](s64)
+    ; CHECK-NEXT: [[ICMP1:%[0-9]+]]:_(s64) = G_ICMP intpred(slt), [[SEXT_INREG]](s64), [[SEXT_INREG1]]
+    ; CHECK-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ICMP1]](s64), [[TRUNC2]], [[SELECT]]
+    ; CHECK-NEXT: [[SEXT:%[0-9]+]]:_(s64) = G_SEXT [[SELECT1]](s32)
+    ; CHECK-NEXT: $x10 = COPY [[SEXT]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %2:_(s64) = COPY $x10
+    %0:_(s32) = G_TRUNC %2(s64)
+    %3:_(s64) = COPY $x11
+    %1:_(s32) = G_TRUNC %3(s64)
+    %4:_(s32) = G_SCMP %0(s32), %1
+    %5:_(s64) = G_SEXT %4(s32)
+    $x10 = COPY %5(s64)
+    PseudoRET implicit $x10
+
+...
+---
+name:            test_scmp_i32
+body:             |
+  bb.1:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: test_scmp_i32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 1
+    ; CHECK-NEXT: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[C]](s64)
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+    ; CHECK-NEXT: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[C1]](s64)
+    ; CHECK-NEXT: [[SEXT_INREG:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY]], 32
+    ; CHECK-NEXT: [[SEXT_INREG1:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY1]], 32
+    ; CHECK-NEXT: [[ICMP:%[0-9]+]]:_(s64) = G_ICMP intpred(sgt), [[SEXT_INREG]](s64), [[SEXT_INREG1]]
+    ; CHECK-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s64), [[TRUNC]], [[TRUNC1]]
+    ; CHECK-NEXT: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 -1
+    ; CHECK-NEXT: [[TRUNC2:%[0-9]+]]:_(s32) = G_TRUNC [[C2]](s64)
+    ; CHECK-NEXT: [[ICMP1:%[0-9]+]]:_(s64) = G_ICMP intpred(slt), [[SEXT_INREG]](s64), [[SEXT_INREG1]]
+    ; CHECK-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ICMP1]](s64), [[TRUNC2]], [[SELECT]]
+    ; CHECK-NEXT: [[SEXT:%[0-9]+]]:_(s64) = G_SEXT [[SELECT1]](s32)
+    ; CHECK-NEXT: $x10 = COPY [[SEXT]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %2:_(s64) = COPY $x10
+    %0:_(s32) = G_TRUNC %2(s64)
+    %3:_(s64) = COPY $x11
+    %1:_(s32) = G_TRUNC %3(s64)
+    %4:_(s32) = G_SCMP %0(s32), %1
+    %5:_(s64) = G_SEXT %4(s32)
+    $x10 = COPY %5(s64)
+    PseudoRET implicit $x10
+
+...

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