[llvm] [RISCV] Teach RISCVMakeCompressible handle byte/half load/store for Zbc. (PR #83375)

Yeting Kuo via llvm-commits llvm-commits at lists.llvm.org
Wed Feb 28 20:44:37 PST 2024


https://github.com/yetingk created https://github.com/llvm/llvm-project/pull/83375

For targets with Zcb, this patch makes llvm generate more compress c.lb/lbu/lh/lhu/sb/sh instructions.

>From 2f357f0198bd904b95fbe24a6e493607d5d16355 Mon Sep 17 00:00:00 2001
From: Yeting Kuo <yeting.kuo at sifive.com>
Date: Thu, 29 Feb 2024 12:43:02 +0800
Subject: [PATCH] [RISCV] Teach RISCVMakeCompressible handle byte/half
 load/store instructions for Zbc.

For targets with Zcb, this patch makes llvm generate more compress
c.lb/lbu/lh/lhu/sb/sh instructions.
---
 .../Target/RISCV/RISCVMakeCompressible.cpp    |  26 +-
 .../CodeGen/RISCV/make-compressible-zbc.mir   | 352 ++++++++++++++++++
 2 files changed, 376 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/CodeGen/RISCV/make-compressible-zbc.mir

diff --git a/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp b/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp
index af864ba0fbc46f..8a1588980a922b 100644
--- a/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp
+++ b/llvm/lib/Target/RISCV/RISCVMakeCompressible.cpp
@@ -99,6 +99,14 @@ static unsigned log2LdstWidth(unsigned Opcode) {
   switch (Opcode) {
   default:
     llvm_unreachable("Unexpected opcode");
+  case RISCV::LB:
+  case RISCV::LBU:
+  case RISCV::SB:
+    return 0;
+  case RISCV::LH:
+  case RISCV::LHU:
+  case RISCV::SH:
+    return 1;
   case RISCV::LW:
   case RISCV::SW:
   case RISCV::FLW:
@@ -121,8 +129,14 @@ static uint8_t compressedLDSTOffsetMask(unsigned Opcode) {
 // Return true if Offset fits within a compressed stack-pointer based
 // load/store.
 static bool compressibleSPOffset(int64_t Offset, unsigned Opcode) {
-  return log2LdstWidth(Opcode) == 2 ? isShiftedUInt<6, 2>(Offset)
-                                    : isShiftedUInt<6, 3>(Offset);
+  // Compressed sp-based loads and stores only work for 32/64 bits.
+  switch (log2LdstWidth(Opcode)) {
+  case 2:
+    return isShiftedUInt<6, 2>(Offset);
+  case 3:
+    return isShiftedUInt<6, 3>(Offset);
+  }
+  return false;
 }
 
 // Given an offset for a load/store, return the adjustment required to the base
@@ -147,6 +161,11 @@ static bool isCompressibleLoad(const MachineInstr &MI) {
   switch (MI.getOpcode()) {
   default:
     return false;
+  case RISCV::LB:
+  case RISCV::LBU:
+  case RISCV::LH:
+  case RISCV::LHU:
+    return STI.hasStdExtZcb();
   case RISCV::LW:
   case RISCV::LD:
     return STI.hasStdExtCOrZca();
@@ -164,6 +183,9 @@ static bool isCompressibleStore(const MachineInstr &MI) {
   switch (MI.getOpcode()) {
   default:
     return false;
+  case RISCV::SB:
+  case RISCV::SH:
+    return STI.hasStdExtZcb();
   case RISCV::SW:
   case RISCV::SD:
     return STI.hasStdExtCOrZca();
diff --git a/llvm/test/CodeGen/RISCV/make-compressible-zbc.mir b/llvm/test/CodeGen/RISCV/make-compressible-zbc.mir
new file mode 100644
index 00000000000000..8121bec3b75e5c
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/make-compressible-zbc.mir
@@ -0,0 +1,352 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -o - %s -mtriple=riscv32 -mattr=+zcb -simplify-mir \
+# RUN:   -run-pass=riscv-make-compressible | FileCheck --check-prefixes=CHECK %s
+# RUN: llc -o - %s -mtriple=riscv64 -mattr=+zcb -simplify-mir \
+# RUN:   -run-pass=riscv-make-compressible | FileCheck --check-prefixes=CHECK %s
+
+--- |
+  define void @store_common_value_i8(ptr %a, ptr %b, ptr %c) #0 {
+  entry:
+    store i8 0, ptr %a, align 1
+    store i8 0, ptr %b, align 1
+    store i8 0, ptr %c, align 1
+    ret void
+  }
+
+  define void @store_common_value_i16(ptr %a, ptr %b, ptr %c) #0 {
+  entry:
+    store i16 0, ptr %a, align 2
+    store i16 0, ptr %b, align 2
+    store i16 0, ptr %c, align 2
+    ret void
+  }
+
+  define void @store_common_ptr_i8(ptr %p) #0 {
+  entry:
+    store volatile i8 1, ptr %p, align 1
+    store volatile i8 3, ptr %p, align 1
+    store volatile i8 5, ptr %p, align 1
+    ret void
+  }
+
+  define void @store_common_ptr_i16(ptr %p) #0 {
+  entry:
+    store volatile i16 1, ptr %p, align 2
+    store volatile i16 3, ptr %p, align 2
+    store volatile i16 5, ptr %p, align 2
+    ret void
+  }
+
+  define void @load_common_ptr_i8(ptr %p) #0 {
+  entry:
+    %0 = load volatile i8, ptr %p, align 1
+    %a = sext i8 %0 to i32
+    %1 = load volatile i8, ptr %p, align 1
+    %2 = load volatile i8, ptr %p, align 1
+    ret void
+  }
+
+  define void @load_common_ptr_i16(ptr %p) #0 {
+  entry:
+    %0 = load volatile i16, ptr %p, align 2
+    %1 = load volatile i16, ptr %p, align 2
+    %2 = load volatile i16, ptr %p, align 2
+    ret void
+  }
+
+  define void @store_large_offset_i8(ptr %p) #0 {
+  entry:
+    %0 = getelementptr inbounds i8, ptr %p, i8 100
+    store volatile i8 1, ptr %0, align 1
+    %1 = getelementptr inbounds i8, ptr %p, i8 101
+    store volatile i8 3, ptr %1, align 1
+    %2 = getelementptr inbounds i8, ptr %p, i8 102
+    store volatile i8 5, ptr %2, align 1
+    %3 = getelementptr inbounds i8, ptr %p, i8 103
+    store volatile i8 7, ptr %3, align 1
+    ret void
+  }
+
+  define void @store_large_offset_i16(ptr %p) #0 {
+  entry:
+    %0 = getelementptr inbounds i16, ptr %p, i16 100
+    store volatile i16 1, ptr %0, align 2
+    %1 = getelementptr inbounds i16, ptr %p, i16 101
+    store volatile i16 3, ptr %1, align 2
+    %2 = getelementptr inbounds i16, ptr %p, i16 102
+    store volatile i16 5, ptr %2, align 2
+    %3 = getelementptr inbounds i16, ptr %p, i16 103
+    store volatile i16 7, ptr %3, align 2
+    ret void
+  }
+
+  define void @load_large_offset_i8(ptr %p) #0 {
+  entry:
+    %0 = getelementptr inbounds i8, ptr %p, i8 100
+    %a = load volatile i8, ptr %0, align 4
+    %1 = getelementptr inbounds i8, ptr %p, i8 101
+    %b = load volatile i8, ptr %1, align 4
+    %2 = getelementptr inbounds i8, ptr %p, i8 102
+    %c = load volatile i8, ptr %2, align 4
+    %3 = getelementptr inbounds i8, ptr %p, i8 103
+    %d = load volatile i8, ptr %3, align 4
+    ret void
+  }
+
+  define void @load_large_offset_i16(ptr %p) #0 {
+  entry:
+    %0 = getelementptr inbounds i16, ptr %p, i16 100
+    %a = load volatile i16, ptr %0, align 4
+    %1 = getelementptr inbounds i16, ptr %p, i16 101
+    %b = load volatile i16, ptr %1, align 4
+    %2 = getelementptr inbounds i16, ptr %p, i16 102
+    %c = load volatile i16, ptr %2, align 4
+    %3 = getelementptr inbounds i16, ptr %p, i16 103
+    %d = load volatile i16, ptr %3, align 4
+    ret void
+  }
+
+  attributes #0 = { minsize }
+
+...
+---
+name:            store_common_value_i8
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11, $x12
+
+    ; CHECK-LABEL: name: store_common_value_i8
+    ; CHECK: liveins: $x10, $x11, $x12
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $x13 = ADDI $x0, 0
+    ; CHECK-NEXT: SB $x13, killed renamable $x10, 0 :: (store (s8) into %ir.a)
+    ; CHECK-NEXT: SB $x13, killed renamable $x11, 0 :: (store (s8) into %ir.b)
+    ; CHECK-NEXT: SB $x13, killed renamable $x12, 0 :: (store (s8) into %ir.c)
+    ; CHECK-NEXT: PseudoRET
+    SB $x0, killed renamable $x10, 0 :: (store (s8) into %ir.a)
+    SB $x0, killed renamable $x11, 0 :: (store (s8) into %ir.b)
+    SB $x0, killed renamable $x12, 0 :: (store (s8) into %ir.c)
+    PseudoRET
+
+...
+---
+name:            store_common_value_i16
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11, $x12
+
+    ; CHECK-LABEL: name: store_common_value_i16
+    ; CHECK: liveins: $x10, $x11, $x12
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $x13 = ADDI $x0, 0
+    ; CHECK-NEXT: SH $x13, killed renamable $x10, 0 :: (store (s16) into %ir.a)
+    ; CHECK-NEXT: SH $x13, killed renamable $x11, 0 :: (store (s16) into %ir.b)
+    ; CHECK-NEXT: SH $x13, killed renamable $x12, 0 :: (store (s16) into %ir.c)
+    ; CHECK-NEXT: PseudoRET
+    SH $x0, killed renamable $x10, 0 :: (store (s16) into %ir.a)
+    SH $x0, killed renamable $x11, 0 :: (store (s16) into %ir.b)
+    SH $x0, killed renamable $x12, 0 :: (store (s16) into %ir.c)
+    PseudoRET
+
+...
+---
+name:            store_common_ptr_i8
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10
+
+    ; CHECK-LABEL: name: store_common_ptr_i8
+    ; CHECK: liveins: $x10
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 1
+    ; CHECK-NEXT: SB killed renamable $x11, renamable $x10, 0 :: (volatile store (s8) into %ir.p)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 3
+    ; CHECK-NEXT: SB killed renamable $x11, renamable $x10, 0 :: (volatile store (s8) into %ir.p)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 5
+    ; CHECK-NEXT: SB killed renamable $x11, killed renamable $x10, 0 :: (volatile store (s8) into %ir.p)
+    ; CHECK-NEXT: PseudoRET
+    renamable $x11 = ADDI $x0, 1
+    SB killed renamable $x11, renamable $x10, 0 :: (volatile store (s8) into %ir.p)
+    renamable $x11 = ADDI $x0, 3
+    SB killed renamable $x11, renamable $x10, 0 :: (volatile store (s8) into %ir.p)
+    renamable $x11 = ADDI $x0, 5
+    SB killed renamable $x11, killed renamable $x10, 0 :: (volatile store (s8) into %ir.p)
+    PseudoRET
+
+...
+---
+name:            store_common_ptr_i16
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10
+
+    ; CHECK-LABEL: name: store_common_ptr_i16
+    ; CHECK: liveins: $x10
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 1
+    ; CHECK-NEXT: SH killed renamable $x11, renamable $x10, 0 :: (volatile store (s16) into %ir.p)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 3
+    ; CHECK-NEXT: SH killed renamable $x11, renamable $x10, 0 :: (volatile store (s16) into %ir.p)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 5
+    ; CHECK-NEXT: SH killed renamable $x11, killed renamable $x10, 0 :: (volatile store (s16) into %ir.p)
+    ; CHECK-NEXT: PseudoRET
+    renamable $x11 = ADDI $x0, 1
+    SH killed renamable $x11, renamable $x10, 0 :: (volatile store (s16) into %ir.p)
+    renamable $x11 = ADDI $x0, 3
+    SH killed renamable $x11, renamable $x10, 0 :: (volatile store (s16) into %ir.p)
+    renamable $x11 = ADDI $x0, 5
+    SH killed renamable $x11, killed renamable $x10, 0 :: (volatile store (s16) into %ir.p)
+    PseudoRET
+
+...
+---
+name:            load_common_ptr_i8
+body:             |
+  bb.0.entry:
+    liveins: $x16
+
+    ; CHECK-LABEL: name: load_common_ptr_i8
+    ; CHECK: liveins: $x16
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $x11 = ADDI $x16, 0
+    ; CHECK-NEXT: dead $x10 = LB $x11, 0 :: (volatile load (s8) from %ir.p)
+    ; CHECK-NEXT: dead $x10 = LB $x11, 0 :: (volatile load (s8) from %ir.p)
+    ; CHECK-NEXT: dead $x10 = LBU killed $x11, 0 :: (volatile load (s8) from %ir.p)
+    ; CHECK-NEXT: PseudoRET
+    dead $x10 = LB renamable $x16, 0 :: (volatile load (s8) from %ir.p)
+    dead $x10 = LB renamable $x16, 0 :: (volatile load (s8) from %ir.p)
+    dead $x10 = LBU killed renamable $x16, 0 :: (volatile load (s8) from %ir.p)
+    PseudoRET
+
+...
+---
+name:            load_common_ptr_i16
+body:             |
+  bb.0.entry:
+    liveins: $x16
+
+    ; CHECK-LABEL: name: load_common_ptr_i16
+    ; CHECK: liveins: $x16
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $x11 = ADDI $x16, 0
+    ; CHECK-NEXT: dead $x10 = LH $x11, 0 :: (volatile load (s16) from %ir.p)
+    ; CHECK-NEXT: dead $x10 = LH $x11, 0 :: (volatile load (s16) from %ir.p)
+    ; CHECK-NEXT: dead $x10 = LHU killed $x11, 0 :: (volatile load (s16) from %ir.p)
+    ; CHECK-NEXT: PseudoRET
+    dead $x10 = LH renamable $x16, 0 :: (volatile load (s16) from %ir.p)
+    dead $x10 = LH renamable $x16, 0 :: (volatile load (s16) from %ir.p)
+    dead $x10 = LHU killed renamable $x16, 0 :: (volatile load (s16) from %ir.p)
+    PseudoRET
+
+...
+---
+name:            store_large_offset_i8
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10
+
+    ; CHECK-LABEL: name: store_large_offset_i8
+    ; CHECK: liveins: $x10
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 1
+    ; CHECK-NEXT: $x12 = ADDI $x10, 96
+    ; CHECK-NEXT: SB killed renamable $x11, $x12, 4 :: (volatile store (s8) into %ir.0)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 3
+    ; CHECK-NEXT: SB killed renamable $x11, $x12, 5 :: (volatile store (s8) into %ir.1)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 5
+    ; CHECK-NEXT: SB killed renamable $x11, $x12, 6 :: (volatile store (s8) into %ir.2)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 7
+    ; CHECK-NEXT: SB killed renamable $x11, killed $x12, 7 :: (volatile store (s8) into %ir.3)
+    ; CHECK-NEXT: PseudoRET
+    renamable $x11 = ADDI $x0, 1
+    SB killed renamable $x11, renamable $x10, 100 :: (volatile store (s8) into %ir.0)
+    renamable $x11 = ADDI $x0, 3
+    SB killed renamable $x11, renamable $x10, 101 :: (volatile store (s8) into %ir.1)
+    renamable $x11 = ADDI $x0, 5
+    SB killed renamable $x11, renamable $x10, 102 :: (volatile store (s8) into %ir.2)
+    renamable $x11 = ADDI $x0, 7
+    SB killed renamable $x11, killed renamable $x10, 103 :: (volatile store (s8) into %ir.3)
+    PseudoRET
+
+...
+---
+name:            store_large_offset_i16
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10
+    ; CHECK-LABEL: name: store_large_offset_i16
+    ; CHECK: liveins: $x10
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 1
+    ; CHECK-NEXT: $x12 = ADDI $x10, 192
+    ; CHECK-NEXT: SH killed renamable $x11, $x12, 8 :: (volatile store (s16) into %ir.0)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 3
+    ; CHECK-NEXT: SH killed renamable $x11, $x12, 10 :: (volatile store (s16) into %ir.1)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 5
+    ; CHECK-NEXT: SH killed renamable $x11, $x12, 12 :: (volatile store (s16) into %ir.2)
+    ; CHECK-NEXT: renamable $x11 = ADDI $x0, 7
+    ; CHECK-NEXT: SH killed renamable $x11, killed $x12, 14 :: (volatile store (s16) into %ir.3)
+    ; CHECK-NEXT: PseudoRET
+    renamable $x11 = ADDI $x0, 1
+    SH killed renamable $x11, renamable $x10, 200 :: (volatile store (s16) into %ir.0)
+    renamable $x11 = ADDI $x0, 3
+    SH killed renamable $x11, renamable $x10, 202 :: (volatile store (s16) into %ir.1)
+    renamable $x11 = ADDI $x0, 5
+    SH killed renamable $x11, renamable $x10, 204 :: (volatile store (s16) into %ir.2)
+    renamable $x11 = ADDI $x0, 7
+    SH killed renamable $x11, killed renamable $x10, 206 :: (volatile store (s16) into %ir.3)
+    PseudoRET
+
+...
+---
+name:            load_large_offset_i8
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x16
+
+    ; CHECK-LABEL: name: load_large_offset_i8
+    ; CHECK: liveins: $x16
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $x11 = ADDI $x16, 384
+    ; CHECK-NEXT: dead $x10 = LB $x11, 16 :: (volatile load (s8) from %ir.0)
+    ; CHECK-NEXT: dead $x10 = LB $x11, 20 :: (volatile load (s8) from %ir.1)
+    ; CHECK-NEXT: dead $x10 = LBU $x11, 24 :: (volatile load (s8) from %ir.2)
+    ; CHECK-NEXT: dead $x10 = LBU killed $x11, 28 :: (volatile load (s8) from %ir.3)
+    ; CHECK-NEXT: PseudoRET
+    dead $x10 = LB renamable $x16, 400 :: (volatile load (s8) from %ir.0)
+    dead $x10 = LB renamable $x16, 404 :: (volatile load (s8) from %ir.1)
+    dead $x10 = LBU renamable $x16, 408 :: (volatile load (s8) from %ir.2)
+    dead $x10 = LBU killed renamable $x16, 412 :: (volatile load (s8) from %ir.3)
+    PseudoRET
+
+...
+---
+name:            load_large_offset_i16
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x16
+
+    ; CHECK-LABEL: name: load_large_offset_i16
+    ; CHECK: liveins: $x16
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $x11 = ADDI $x16, 384
+    ; CHECK-NEXT: dead $x10 = LB $x11, 16 :: (volatile load (s16) from %ir.0)
+    ; CHECK-NEXT: dead $x10 = LB $x11, 20 :: (volatile load (s16) from %ir.1)
+    ; CHECK-NEXT: dead $x10 = LBU $x11, 24 :: (volatile load (s16) from %ir.2)
+    ; CHECK-NEXT: dead $x10 = LBU killed $x11, 28 :: (volatile load (s16) from %ir.3)
+    ; CHECK-NEXT: PseudoRET
+    dead $x10 = LB renamable $x16, 400 :: (volatile load (s16) from %ir.0)
+    dead $x10 = LB renamable $x16, 404 :: (volatile load (s16) from %ir.1)
+    dead $x10 = LBU renamable $x16, 408 :: (volatile load (s16) from %ir.2)
+    dead $x10 = LBU killed renamable $x16, 412 :: (volatile load (s16) from %ir.3)
+    PseudoRET
+
+...



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