[llvm] 71b5f57 - [RISCV] Adjust first sp size to use c.addi16sp.
Jie Fu via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 5 23:32:26 PDT 2023
Author: laichunfeng
Date: 2023-09-06T14:26:52+08:00
New Revision: 71b5f57f0d7dfd79211f09d53f2baaaa205984a2
URL: https://github.com/llvm/llvm-project/commit/71b5f57f0d7dfd79211f09d53f2baaaa205984a2
DIFF: https://github.com/llvm/llvm-project/commit/71b5f57f0d7dfd79211f09d53f2baaaa205984a2.diff
LOG: [RISCV] Adjust first sp size to use c.addi16sp.
addi sp, sp, 512 may be used to recover the sp in the epilogue
when stack size is larger than 2047(2^11 - 1), however, it can
not be compressed using C extension, and addi sp, sp, 496 is
able to be compressed, so try to use 496 as the ajust amount of
the fisrt sp if function doesn't need extra instructions after
adjust.
Reviewed By: wangpc
Differential Revision: https://reviews.llvm.org/D159431
Added:
Modified:
llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
llvm/test/CodeGen/RISCV/stack-inst-compress.mir
Removed:
################################################################################
diff --git a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
index 0588cfa6dbafbe3..add933250f8473d 100644
--- a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
@@ -1278,7 +1278,8 @@ MachineBasicBlock::iterator RISCVFrameLowering::eliminateCallFramePseudoInstr(
// We would like to split the SP adjustment to reduce prologue/epilogue
// as following instructions. In this way, the offset of the callee saved
-// register could fit in a single store.
+// register could fit in a single store. Supposed that the first sp adjust
+// amount is 2032.
// add sp,sp,-2032
// sw ra,2028(sp)
// sw s0,2024(sp)
@@ -1315,6 +1316,7 @@ RISCVFrameLowering::getFirstSPAdjustAmount(const MachineFunction &MF) const {
// offset that stack compression instructions accept when target supports
// compression instructions.
if (STI.hasStdExtCOrZca()) {
+ // The compression extensions may support the following instructions:
// riscv32: c.lwsp rd, offset[7:2] => 2^(6 + 2)
// c.swsp rs2, offset[7:2] => 2^(6 + 2)
// c.flwsp rd, offset[7:2] => 2^(6 + 2)
@@ -1330,10 +1332,22 @@ RISCVFrameLowering::getFirstSPAdjustAmount(const MachineFunction &MF) const {
// StackSize meets the condition (StackSize <= 2048 + RVCompressLen),
// case1: Amount is 2048 - StackAlign: use addi + addi to adjust sp.
// case2: Amount is RVCompressLen: use addi + addi to adjust sp.
- if (StackSize <= 2047 + RVCompressLen ||
- (StackSize > 2048 * 2 - StackAlign &&
- StackSize <= 2047 * 2 + RVCompressLen) ||
- StackSize > 2048 * 3 - StackAlign)
+ auto CanCompress = [&](uint64_t CompressLen) -> bool {
+ if (StackSize <= 2047 + CompressLen ||
+ (StackSize > 2048 * 2 - StackAlign &&
+ StackSize <= 2047 * 2 + CompressLen) ||
+ StackSize > 2048 * 3 - StackAlign)
+ return true;
+
+ return false;
+ };
+ // In the epilogue, addi sp, sp, 496 is used to recover the sp and it
+ // can be compressed(C.ADDI16SP, offset can be [-512, 496]), but
+ // addi sp, sp, 512 can not be compressed. So try to use 496 first.
+ const uint64_t ADDI16SPCompressLen = 496;
+ if (STI.is64Bit() && CanCompress(ADDI16SPCompressLen))
+ return ADDI16SPCompressLen;
+ if (CanCompress(RVCompressLen))
return RVCompressLen;
}
return 2048 - StackAlign;
diff --git a/llvm/test/CodeGen/RISCV/stack-inst-compress.mir b/llvm/test/CodeGen/RISCV/stack-inst-compress.mir
index 44a30b77f2e460c..5dcf1e9f8cbbf20 100644
--- a/llvm/test/CodeGen/RISCV/stack-inst-compress.mir
+++ b/llvm/test/CodeGen/RISCV/stack-inst-compress.mir
@@ -92,17 +92,17 @@ body: |
; CHECK-RV64-COM-LABEL: name: _Z15stack_size_2048v
; CHECK-RV64-COM: liveins: $x1
; CHECK-RV64-COM-NEXT: {{ $}}
- ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -512
- ; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 512
- ; CHECK-RV64-COM-NEXT: SD killed $x1, $x2, 504 :: (store (s64) into %stack.1)
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -496
+ ; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 496
+ ; CHECK-RV64-COM-NEXT: SD killed $x1, $x2, 488 :: (store (s64) into %stack.1)
; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION offset $x1, -8
- ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -1552
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -1568
; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 2064
; CHECK-RV64-COM-NEXT: renamable $x10 = ADDI $x2, 8
; CHECK-RV64-COM-NEXT: PseudoCALL target-flags(riscv-call) @_Z6calleePi, csr_ilp32_lp64, implicit-def dead $x1, implicit killed $x10, implicit-def $x2
- ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 1552
- ; CHECK-RV64-COM-NEXT: $x1 = LD $x2, 504 :: (load (s64) from %stack.1)
- ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 512
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 1568
+ ; CHECK-RV64-COM-NEXT: $x1 = LD $x2, 488 :: (load (s64) from %stack.1)
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 496
; CHECK-RV64-COM-NEXT: PseudoRET
ADJCALLSTACKDOWN 0, 0, implicit-def dead $x2, implicit $x2
renamable $x10 = ADDI %stack.0, 0
@@ -183,19 +183,19 @@ body: |
; CHECK-RV64-COM-LABEL: name: _Z15stack_size_4096v
; CHECK-RV64-COM: liveins: $x1
; CHECK-RV64-COM-NEXT: {{ $}}
- ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -512
- ; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 512
- ; CHECK-RV64-COM-NEXT: SD killed $x1, $x2, 504 :: (store (s64) into %stack.1)
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -496
+ ; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 496
+ ; CHECK-RV64-COM-NEXT: SD killed $x1, $x2, 488 :: (store (s64) into %stack.1)
; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION offset $x1, -8
; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -2048
- ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI killed $x2, -1552
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI killed $x2, -1568
; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 4112
; CHECK-RV64-COM-NEXT: renamable $x10 = ADDI $x2, 8
; CHECK-RV64-COM-NEXT: PseudoCALL target-flags(riscv-call) @_Z6calleePi, csr_ilp32_lp64, implicit-def dead $x1, implicit killed $x10, implicit-def $x2
; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 2032
- ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI killed $x2, 1568
- ; CHECK-RV64-COM-NEXT: $x1 = LD $x2, 504 :: (load (s64) from %stack.1)
- ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 512
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI killed $x2, 1584
+ ; CHECK-RV64-COM-NEXT: $x1 = LD $x2, 488 :: (load (s64) from %stack.1)
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 496
; CHECK-RV64-COM-NEXT: PseudoRET
ADJCALLSTACKDOWN 0, 0, implicit-def dead $x2, implicit $x2
renamable $x10 = ADDI %stack.0, 0
@@ -282,21 +282,21 @@ body: |
; CHECK-RV64-COM-LABEL: name: _Z15stack_size_8192v
; CHECK-RV64-COM: liveins: $x1
; CHECK-RV64-COM-NEXT: {{ $}}
- ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -512
- ; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 512
- ; CHECK-RV64-COM-NEXT: SD killed $x1, $x2, 504 :: (store (s64) into %stack.1)
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-setup ADDI $x2, -496
+ ; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 496
+ ; CHECK-RV64-COM-NEXT: SD killed $x1, $x2, 488 :: (store (s64) into %stack.1)
; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION offset $x1, -8
; CHECK-RV64-COM-NEXT: $x10 = frame-setup LUI 2
- ; CHECK-RV64-COM-NEXT: $x10 = frame-setup ADDIW killed $x10, -496
+ ; CHECK-RV64-COM-NEXT: $x10 = frame-setup ADDIW killed $x10, -480
; CHECK-RV64-COM-NEXT: $x2 = frame-setup SUB $x2, killed $x10
; CHECK-RV64-COM-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 8208
; CHECK-RV64-COM-NEXT: renamable $x10 = ADDI $x2, 8
; CHECK-RV64-COM-NEXT: PseudoCALL target-flags(riscv-call) @_Z6calleePi, csr_ilp32_lp64, implicit-def dead $x1, implicit killed $x10, implicit-def $x2
; CHECK-RV64-COM-NEXT: $x10 = frame-destroy LUI 2
- ; CHECK-RV64-COM-NEXT: $x10 = frame-destroy ADDIW killed $x10, -496
+ ; CHECK-RV64-COM-NEXT: $x10 = frame-destroy ADDIW killed $x10, -480
; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADD $x2, killed $x10
- ; CHECK-RV64-COM-NEXT: $x1 = LD $x2, 504 :: (load (s64) from %stack.1)
- ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 512
+ ; CHECK-RV64-COM-NEXT: $x1 = LD $x2, 488 :: (load (s64) from %stack.1)
+ ; CHECK-RV64-COM-NEXT: $x2 = frame-destroy ADDI $x2, 496
; CHECK-RV64-COM-NEXT: PseudoRET
ADJCALLSTACKDOWN 0, 0, implicit-def dead $x2, implicit $x2
renamable $x10 = ADDI %stack.0, 0
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