[llvm] [RISCV] Use LD_RV32/SD_RV32 for spills and reloads when Zilsd is enabled (PR #153595)
Sam Elliott via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 14 13:20:40 PDT 2025
================
@@ -1,44 +1,81 @@
; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
-; RUN: llc < %s -mtriple=riscv32 -mattr=+zdinx -verify-machineinstrs -stop-after=prologepilog | FileCheck %s
+; RUN: llc < %s -mtriple=riscv32 -mattr=+zdinx -verify-machineinstrs -stop-after=prologepilog | FileCheck %s -check-prefix=ZDINX
+; RUN: llc < %s -mtriple=riscv32 -mattr=+zdinx,+zilsd -verify-machineinstrs -stop-after=prologepilog | FileCheck %s -check-prefix=ZDINX-ZILSD
declare void @bar()
define double @foo(double %x) nounwind {
- ; CHECK-LABEL: name: foo
- ; CHECK: bb.0 (%ir-block.0):
- ; CHECK-NEXT: liveins: $x10, $x11, $x8, $x9, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27
- ; CHECK-NEXT: {{ $}}
- ; CHECK-NEXT: $x2 = frame-setup ADDI $x2, -64
- ; CHECK-NEXT: frame-setup SW killed $x8, $x2, 60 :: (store (s32) into %stack.1)
- ; CHECK-NEXT: frame-setup SW killed $x9, $x2, 56 :: (store (s32) into %stack.2)
- ; CHECK-NEXT: frame-setup SW killed $x18, $x2, 52 :: (store (s32) into %stack.3)
- ; CHECK-NEXT: frame-setup SW killed $x19, $x2, 48 :: (store (s32) into %stack.4)
- ; CHECK-NEXT: frame-setup SW killed $x20, $x2, 44 :: (store (s32) into %stack.5)
- ; CHECK-NEXT: frame-setup SW killed $x21, $x2, 40 :: (store (s32) into %stack.6)
- ; CHECK-NEXT: frame-setup SW killed $x22, $x2, 36 :: (store (s32) into %stack.7)
- ; CHECK-NEXT: frame-setup SW killed $x23, $x2, 32 :: (store (s32) into %stack.8)
- ; CHECK-NEXT: frame-setup SW killed $x24, $x2, 28 :: (store (s32) into %stack.9)
- ; CHECK-NEXT: frame-setup SW killed $x25, $x2, 24 :: (store (s32) into %stack.10)
- ; CHECK-NEXT: frame-setup SW killed $x26, $x2, 20 :: (store (s32) into %stack.11)
- ; CHECK-NEXT: frame-setup SW killed $x27, $x2, 16 :: (store (s32) into %stack.12)
- ; CHECK-NEXT: renamable $x10_x11 = nofpexcept FADD_D_IN32X killed renamable $x10_x11, renamable $x10_x11, 7, implicit $frm
- ; CHECK-NEXT: PseudoRV32ZdinxSD killed renamable $x10_x11, $x2, 8 :: (store (s64) into %stack.0, align 4)
- ; CHECK-NEXT: INLINEASM &"", 1 /* sideeffect attdialect */, 12 /* clobber */, implicit-def dead early-clobber $x6, 12 /* clobber */, implicit-def dead early-clobber $x7, 12 /* clobber */, implicit-def dead early-clobber $x8, 12 /* clobber */, implicit-def dead early-clobber $x9, 12 /* clobber */, implicit-def dead early-clobber $x10, 12 /* clobber */, implicit-def dead early-clobber $x11, 12 /* clobber */, implicit-def dead early-clobber $x12, 12 /* clobber */, implicit-def dead early-clobber $x13, 12 /* clobber */, implicit-def dead early-clobber $x14, 12 /* clobber */, implicit-def dead early-clobber $x15, 12 /* clobber */, implicit-def dead early-clobber $x16, 12 /* clobber */, implicit-def dead early-clobber $x17, 12 /* clobber */, implicit-def dead early-clobber $x18, 12 /* clobber */, implicit-def dead early-clobber $x19, 12 /* clobber */, implicit-def dead early-clobber $x20, 12 /* clobber */, implicit-def dead early-clobber $x21, 12 /* clobber */, implicit-def dead early-clobber $x22, 12 /* clobber */, implicit-def dead early-clobber $x23, 12 /* clobber */, implicit-def dead early-clobber $x24, 12 /* clobber */, implicit-def dead early-clobber $x25, 12 /* clobber */, implicit-def dead early-clobber $x26, 12 /* clobber */, implicit-def dead early-clobber $x27, 12 /* clobber */, implicit-def dead early-clobber $x28, 12 /* clobber */, implicit-def dead early-clobber $x29, 12 /* clobber */, implicit-def dead early-clobber $x31
- ; CHECK-NEXT: renamable $x10_x11 = PseudoRV32ZdinxLD $x2, 8 :: (load (s64) from %stack.0, align 4)
- ; CHECK-NEXT: $x8 = frame-destroy LW $x2, 60 :: (load (s32) from %stack.1)
- ; CHECK-NEXT: $x9 = frame-destroy LW $x2, 56 :: (load (s32) from %stack.2)
- ; CHECK-NEXT: $x18 = frame-destroy LW $x2, 52 :: (load (s32) from %stack.3)
- ; CHECK-NEXT: $x19 = frame-destroy LW $x2, 48 :: (load (s32) from %stack.4)
- ; CHECK-NEXT: $x20 = frame-destroy LW $x2, 44 :: (load (s32) from %stack.5)
- ; CHECK-NEXT: $x21 = frame-destroy LW $x2, 40 :: (load (s32) from %stack.6)
- ; CHECK-NEXT: $x22 = frame-destroy LW $x2, 36 :: (load (s32) from %stack.7)
- ; CHECK-NEXT: $x23 = frame-destroy LW $x2, 32 :: (load (s32) from %stack.8)
- ; CHECK-NEXT: $x24 = frame-destroy LW $x2, 28 :: (load (s32) from %stack.9)
- ; CHECK-NEXT: $x25 = frame-destroy LW $x2, 24 :: (load (s32) from %stack.10)
- ; CHECK-NEXT: $x26 = frame-destroy LW $x2, 20 :: (load (s32) from %stack.11)
- ; CHECK-NEXT: $x27 = frame-destroy LW $x2, 16 :: (load (s32) from %stack.12)
- ; CHECK-NEXT: $x2 = frame-destroy ADDI $x2, 64
- ; CHECK-NEXT: PseudoRET implicit $x10, implicit $x11
+ ; ZDINX-LABEL: name: foo
+ ; ZDINX: bb.0 (%ir-block.0):
+ ; ZDINX-NEXT: liveins: $x10, $x11, $x8, $x9, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27
+ ; ZDINX-NEXT: {{ $}}
+ ; ZDINX-NEXT: $x2 = frame-setup ADDI $x2, -64
+ ; ZDINX-NEXT: frame-setup SW killed $x8, $x2, 60 :: (store (s32) into %stack.1)
+ ; ZDINX-NEXT: frame-setup SW killed $x9, $x2, 56 :: (store (s32) into %stack.2)
+ ; ZDINX-NEXT: frame-setup SW killed $x18, $x2, 52 :: (store (s32) into %stack.3)
+ ; ZDINX-NEXT: frame-setup SW killed $x19, $x2, 48 :: (store (s32) into %stack.4)
+ ; ZDINX-NEXT: frame-setup SW killed $x20, $x2, 44 :: (store (s32) into %stack.5)
+ ; ZDINX-NEXT: frame-setup SW killed $x21, $x2, 40 :: (store (s32) into %stack.6)
+ ; ZDINX-NEXT: frame-setup SW killed $x22, $x2, 36 :: (store (s32) into %stack.7)
+ ; ZDINX-NEXT: frame-setup SW killed $x23, $x2, 32 :: (store (s32) into %stack.8)
+ ; ZDINX-NEXT: frame-setup SW killed $x24, $x2, 28 :: (store (s32) into %stack.9)
+ ; ZDINX-NEXT: frame-setup SW killed $x25, $x2, 24 :: (store (s32) into %stack.10)
+ ; ZDINX-NEXT: frame-setup SW killed $x26, $x2, 20 :: (store (s32) into %stack.11)
+ ; ZDINX-NEXT: frame-setup SW killed $x27, $x2, 16 :: (store (s32) into %stack.12)
+ ; ZDINX-NEXT: renamable $x10_x11 = nofpexcept FADD_D_IN32X killed renamable $x10_x11, renamable $x10_x11, 7, implicit $frm
+ ; ZDINX-NEXT: PseudoRV32ZdinxSD killed renamable $x10_x11, $x2, 8 :: (store (s64) into %stack.0, align 4)
+ ; ZDINX-NEXT: INLINEASM &"", 1 /* sideeffect attdialect */, 12 /* clobber */, implicit-def dead early-clobber $x6, 12 /* clobber */, implicit-def dead early-clobber $x7, 12 /* clobber */, implicit-def dead early-clobber $x8, 12 /* clobber */, implicit-def dead early-clobber $x9, 12 /* clobber */, implicit-def dead early-clobber $x10, 12 /* clobber */, implicit-def dead early-clobber $x11, 12 /* clobber */, implicit-def dead early-clobber $x12, 12 /* clobber */, implicit-def dead early-clobber $x13, 12 /* clobber */, implicit-def dead early-clobber $x14, 12 /* clobber */, implicit-def dead early-clobber $x15, 12 /* clobber */, implicit-def dead early-clobber $x16, 12 /* clobber */, implicit-def dead early-clobber $x17, 12 /* clobber */, implicit-def dead early-clobber $x18, 12 /* clobber */, implicit-def dead early-clobber $x19, 12 /* clobber */, implicit-def dead early-clobber $x20, 12 /* clobber */, implicit-def dead early-clobber $x21, 12 /* clobber */, implicit-def dead early-clobber $x22, 12 /* clobber */, implicit-def dead early-clobber $x23, 12 /* clobber */, implicit-def dead early-clobber $x24, 12 /* clobber */, implicit-def dead early-clobber $x25, 12 /* clobber */, implicit-def dead early-clobber $x26, 12 /* clobber */, implicit-def dead early-clobber $x27, 12 /* clobber */, implicit-def dead early-clobber $x28, 12 /* clobber */, implicit-def dead early-clobber $x29, 12 /* clobber */, implicit-def dead early-clobber $x31
+ ; ZDINX-NEXT: renamable $x10_x11 = PseudoRV32ZdinxLD $x2, 8 :: (load (s64) from %stack.0, align 4)
+ ; ZDINX-NEXT: $x8 = frame-destroy LW $x2, 60 :: (load (s32) from %stack.1)
+ ; ZDINX-NEXT: $x9 = frame-destroy LW $x2, 56 :: (load (s32) from %stack.2)
+ ; ZDINX-NEXT: $x18 = frame-destroy LW $x2, 52 :: (load (s32) from %stack.3)
+ ; ZDINX-NEXT: $x19 = frame-destroy LW $x2, 48 :: (load (s32) from %stack.4)
+ ; ZDINX-NEXT: $x20 = frame-destroy LW $x2, 44 :: (load (s32) from %stack.5)
+ ; ZDINX-NEXT: $x21 = frame-destroy LW $x2, 40 :: (load (s32) from %stack.6)
+ ; ZDINX-NEXT: $x22 = frame-destroy LW $x2, 36 :: (load (s32) from %stack.7)
+ ; ZDINX-NEXT: $x23 = frame-destroy LW $x2, 32 :: (load (s32) from %stack.8)
+ ; ZDINX-NEXT: $x24 = frame-destroy LW $x2, 28 :: (load (s32) from %stack.9)
+ ; ZDINX-NEXT: $x25 = frame-destroy LW $x2, 24 :: (load (s32) from %stack.10)
+ ; ZDINX-NEXT: $x26 = frame-destroy LW $x2, 20 :: (load (s32) from %stack.11)
+ ; ZDINX-NEXT: $x27 = frame-destroy LW $x2, 16 :: (load (s32) from %stack.12)
+ ; ZDINX-NEXT: $x2 = frame-destroy ADDI $x2, 64
+ ; ZDINX-NEXT: PseudoRET implicit $x10, implicit $x11
+ ;
+ ; ZDINX-ZILSD-LABEL: name: foo
+ ; ZDINX-ZILSD: bb.0 (%ir-block.0):
+ ; ZDINX-ZILSD-NEXT: liveins: $x10, $x11, $x8, $x9, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27
+ ; ZDINX-ZILSD-NEXT: {{ $}}
+ ; ZDINX-ZILSD-NEXT: $x2 = frame-setup ADDI $x2, -64
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x8, $x2, 60 :: (store (s32) into %stack.1)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x9, $x2, 56 :: (store (s32) into %stack.2)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x18, $x2, 52 :: (store (s32) into %stack.3)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x19, $x2, 48 :: (store (s32) into %stack.4)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x20, $x2, 44 :: (store (s32) into %stack.5)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x21, $x2, 40 :: (store (s32) into %stack.6)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x22, $x2, 36 :: (store (s32) into %stack.7)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x23, $x2, 32 :: (store (s32) into %stack.8)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x24, $x2, 28 :: (store (s32) into %stack.9)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x25, $x2, 24 :: (store (s32) into %stack.10)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x26, $x2, 20 :: (store (s32) into %stack.11)
+ ; ZDINX-ZILSD-NEXT: frame-setup SW killed $x27, $x2, 16 :: (store (s32) into %stack.12)
+ ; ZDINX-ZILSD-NEXT: renamable $x10_x11 = nofpexcept FADD_D_IN32X killed renamable $x10_x11, renamable $x10_x11, 7, implicit $frm
+ ; ZDINX-ZILSD-NEXT: SD_RV32 killed renamable $x10_x11, $x2, 8 :: (store (s64) into %stack.0, align 4)
----------------
lenary wrote:
Yeah. The spill alignment for pairs matches the spill alignment for GPRs, rather than matching the natural alignment of pairs.
I think increasing the spill width is possible, but would cause issues on `ilp32e` as you point out, as we find it hard to spill D registers already with that combo, due to stack realignment.
Thankfully, the spill alignment is not an ABI detail, so we can try to make better choices, but annoyingly it's also controlled by tablegen info which we cannot override easily (this does not warrant new HWModes, which would be the only way to change it).
We're thinking about other ideas here, including about how we are handling alignment on rv32 - but we're also in the final days before our own release freeze, so capacity for our team to do a larger fix is not available immediately.
https://github.com/llvm/llvm-project/pull/153595
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