[llvm] [X86InstrInfo] support memfold on spillable inline asm (PR #70832)

Nick Desaulniers via llvm-commits llvm-commits at lists.llvm.org
Tue Nov 21 15:03:05 PST 2023


================
@@ -0,0 +1,232 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 3
+# RUN: llc -start-after=finalize-isel -regalloc=greedy -stop-after=greedy \
+# RUN:   -verify-machineinstrs -verify-regalloc %s -o - | FileCheck %s
+--- |
+  target datalayout = "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-i128:128-f64:32:64-f80:32-n8:16:32-S128"
+  target triple = "i386-unknown-linux-gnu"
+
+  define void @input(i32 %0) #0 {
+    call void asm "# $0", "rm,~{ax},~{cx},~{dx},~{si},~{di},~{bx},~{bp}"(i32 %0)
+    ret void
+  }
+
+  define i32 @output() #0 {
+    %1 = alloca i32, align 4
+    call void asm "# $0", "=*rm,~{ax},~{cx},~{dx},~{si},~{di},~{bx},~{bp}"(ptr nonnull elementtype(i32) %1)
+    %2 = load i32, ptr %1, align 4
+    ret i32 %2
+  }
+
+  define i32 @inout(i32 %0) #0 {
+    %2 = alloca i32, align 4
+    store i32 %0, ptr %2, align 4
+    call void asm "# $0 $1", "=*rm,0,~{ax},~{cx},~{dx},~{si},~{di},~{bx},~{bp}"(ptr nonnull elementtype(i32) %2, i32 %0)
+    %3 = load i32, ptr %2, align 4
+    ret i32 %3
+  }
+
+  attributes #0 = { nounwind }
+
+...
+---
+name:            input
+alignment:       16
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+callsEHReturn:   false
+callsUnwindInit: false
+hasEHCatchret:   false
+hasEHScopes:     false
+hasEHFunclets:   false
+isOutlined:      false
+debugInstrRef:   false
+failsVerification: false
+tracksDebugUserValues: false
+registers:
+  - { id: 0, class: gr32, preferred-register: '' }
+liveins:         []
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    4
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  functionContext: ''
+  maxCallFrameSize: 4294967295
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  hasTailCall:     false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+  - { id: 0, type: default, offset: 0, size: 4, alignment: 16, stack-id: default,
+      isImmutable: true, isAliased: false, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+stack:           []
+entry_values:    []
+callSites:       []
+debugValueSubstitutions: []
+constants:       []
+machineFunctionInfo: {}
+body:             |
+  bb.0 (%ir-block.1):
+    ; CHECK-LABEL: name: input
+    ; CHECK: INLINEASM &"# $0", 8 /* mayload attdialect */, 262190 /* mem:m */, %fixed-stack.0, 1, $noreg, 0, $noreg, 12 /* clobber */, implicit-def dead early-clobber $ax, 12 /* clobber */, implicit-def dead early-clobber $cx, 12 /* clobber */, implicit-def dead early-clobber $dx, 12 /* clobber */, implicit-def dead early-clobber $si, 12 /* clobber */, implicit-def dead early-clobber $di, 12 /* clobber */, implicit-def dead early-clobber $bx, 12 /* clobber */, implicit-def dead early-clobber $bp :: (load (s32) from %fixed-stack.0, align 16)
+    ; CHECK-NEXT: RET 0
+    %0:gr32 = MOV32rm %fixed-stack.0, 1, $noreg, 0, $noreg :: (load (s32) from %fixed-stack.0, align 16)
+    INLINEASM &"# $0", 0 /* attdialect */, 1076101129 /* reguse:GR32 spillable */, %0, 12 /* clobber */, implicit-def early-clobber $ax, 12 /* clobber */, implicit-def early-clobber $cx, 12 /* clobber */, implicit-def early-clobber $dx, 12 /* clobber */, implicit-def early-clobber $si, 12 /* clobber */, implicit-def early-clobber $di, 12 /* clobber */, implicit-def early-clobber $bx, 12 /* clobber */, implicit-def early-clobber $bp
+    RET 0
+
+...
+---
+name:            output
+alignment:       16
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+callsEHReturn:   false
+callsUnwindInit: false
+hasEHCatchret:   false
+hasEHScopes:     false
+hasEHFunclets:   false
+isOutlined:      false
+debugInstrRef:   false
+failsVerification: false
+tracksDebugUserValues: false
+registers:
+  - { id: 0, class: gr32, preferred-register: '' }
+liveins:         []
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    4
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  functionContext: ''
+  maxCallFrameSize: 4294967295
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  hasTailCall:     false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:      []
+stack:
+  - { id: 0, name: '', type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+entry_values:    []
+callSites:       []
+debugValueSubstitutions: []
+constants:       []
+machineFunctionInfo: {}
+body:             |
+  bb.0 (%ir-block.0):
+    ; CHECK-LABEL: name: output
+    ; CHECK: INLINEASM &"# $0", 16 /* maystore attdialect */, 262190 /* mem:m */, %stack.1, 1, $noreg, 0, $noreg, 12 /* clobber */, implicit-def dead early-clobber $ax, 12 /* clobber */, implicit-def dead early-clobber $cx, 12 /* clobber */, implicit-def dead early-clobber $dx, 12 /* clobber */, implicit-def dead early-clobber $si, 12 /* clobber */, implicit-def dead early-clobber $di, 12 /* clobber */, implicit-def dead early-clobber $bx, 12 /* clobber */, implicit-def dead early-clobber $bp :: (store (s32) into %stack.1)
+    ; CHECK-NEXT: [[MOV32rm:%[0-9]+]]:gr32 = MOV32rm %stack.1, 1, $noreg, 0, $noreg :: (load (s32) from %stack.1)
+    ; CHECK-NEXT: MOV32mr %stack.0, 1, $noreg, 0, $noreg, [[MOV32rm]] :: (store (s32) into %ir.1)
+    ; CHECK-NEXT: $eax = COPY [[MOV32rm]]
+    ; CHECK-NEXT: RET 0, $eax
+    INLINEASM &"# $0", 0 /* attdialect */, 1076101130 /* regdef:GR32 spillable */, def %0, 12 /* clobber */, implicit-def early-clobber $ax, 12 /* clobber */, implicit-def early-clobber $cx, 12 /* clobber */, implicit-def early-clobber $dx, 12 /* clobber */, implicit-def early-clobber $si, 12 /* clobber */, implicit-def early-clobber $di, 12 /* clobber */, implicit-def early-clobber $bx, 12 /* clobber */, implicit-def early-clobber $bp
+    MOV32mr %stack.0, 1, $noreg, 0, $noreg, %0 :: (store (s32) into %ir.1)
+    $eax = COPY %0
+    RET 0, $eax
+
+...
+---
+name:            inout
+alignment:       16
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+callsEHReturn:   false
+callsUnwindInit: false
+hasEHCatchret:   false
+hasEHScopes:     false
+hasEHFunclets:   false
+isOutlined:      false
+debugInstrRef:   false
+failsVerification: false
+tracksDebugUserValues: false
+registers:
+  - { id: 0, class: gr32, preferred-register: '' }
+  - { id: 1, class: gr32, preferred-register: '' }
+liveins:         []
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    4
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  functionContext: ''
+  maxCallFrameSize: 4294967295
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  hasTailCall:     false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+  - { id: 0, type: default, offset: 0, size: 4, alignment: 16, stack-id: default,
+      isImmutable: false, isAliased: false, callee-saved-register: '',
+      callee-saved-restored: true, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+stack:           []
+entry_values:    []
+callSites:       []
+debugValueSubstitutions: []
+constants:       []
+machineFunctionInfo: {}
+body:             |
+  bb.0 (%ir-block.1):
+    ; CHECK-LABEL: name: inout
+    ; CHECK: [[MOV32rm:%[0-9]+]]:gr32 = MOV32rm %fixed-stack.0, 1, $noreg, 0, $noreg :: (load (s32) from %fixed-stack.0, align 16)
+    ; CHECK-NEXT: MOV32mr %stack.0, 1, $noreg, 0, $noreg, [[MOV32rm]] :: (store (s32) into %stack.0)
+    ; CHECK-NEXT: INLINEASM &"# $0 $1", 24 /* mayload maystore attdialect */, 262190 /* mem:m */, %stack.0, 1, $noreg, 0, $noreg, 262190 /* mem:m */, %stack.0, 1, $noreg, 0, $noreg, 12 /* clobber */, implicit-def dead early-clobber $ax, 12 /* clobber */, implicit-def dead early-clobber $cx, 12 /* clobber */, implicit-def dead early-clobber $dx, 12 /* clobber */, implicit-def dead early-clobber $si, 12 /* clobber */, implicit-def dead early-clobber $di, 12 /* clobber */, implicit-def dead early-clobber $bx, 12 /* clobber */, implicit-def dead early-clobber $bp :: (store (s32) into %stack.0)
----------------
nickdesaulniers wrote:

> Let me do some debugging of the print method and see if I can give you a more precise answer FWIW.

I believe it's a loop in MachineInstr::print that's iterating the memoperands() of the MachineInstr and calling print on them.

I'm not super familiar with the MachineMemOperand class. Let me triple check whether that loop is indeed the one printing the load/store, and if so, do I need to modify the memoperands() of the MachineInstr (beyond setting the extra info which is very specific to INLINEASM).

https://github.com/llvm/llvm-project/pull/70832


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