[llvm] r349151 - [RegAllocGreedy] IMPLICIT_DEF values shouldn't prefer registers
John Brawn via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 14 06:07:57 PST 2018
Author: john.brawn
Date: Fri Dec 14 06:07:57 2018
New Revision: 349151
URL: http://llvm.org/viewvc/llvm-project?rev=349151&view=rev
Log:
[RegAllocGreedy] IMPLICIT_DEF values shouldn't prefer registers
It costs nothing to spill an IMPLICIT_DEF value (the only spill code that's
generated is a KILL of the value), so when creating split constraints if the
live-out value is IMPLICIT_DEF the exit constraint should be DontCare instead
of PrefReg.
Differential Revision: https://reviews.llvm.org/D55652
Added:
llvm/trunk/test/CodeGen/Thumb/ragreedy-implicit-def.ll
Modified:
llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp
llvm/trunk/test/CodeGen/AMDGPU/subreg-split-live-in-error.mir
llvm/trunk/test/CodeGen/X86/pr38795.ll
Modified: llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp?rev=349151&r1=349150&r2=349151&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp Fri Dec 14 06:07:57 2018
@@ -1183,7 +1183,10 @@ bool RAGreedy::addSplitConstraints(Inter
BC.Number = BI.MBB->getNumber();
Intf.moveToBlock(BC.Number);
BC.Entry = BI.LiveIn ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
- BC.Exit = BI.LiveOut ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
+ BC.Exit = (BI.LiveOut &&
+ !LIS->getInstructionFromIndex(BI.LastInstr)->isImplicitDef())
+ ? SpillPlacement::PrefReg
+ : SpillPlacement::DontCare;
BC.ChangesValue = BI.FirstDef.isValid();
if (!Intf.hasInterference())
Modified: llvm/trunk/test/CodeGen/AMDGPU/subreg-split-live-in-error.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/subreg-split-live-in-error.mir?rev=349151&r1=349150&r2=349151&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/subreg-split-live-in-error.mir (original)
+++ llvm/trunk/test/CodeGen/AMDGPU/subreg-split-live-in-error.mir Fri Dec 14 06:07:57 2018
@@ -102,6 +102,13 @@ body: |
bb.7:
successors: %bb.13(0x80000000)
+
+ ; In reality we are checking that this code doesn't assert when splitting
+ ; and inserting a spill. Here we just check that the point where the error
+ ; occurs we see a correctly generated spill.
+ ; GCN-LABEL: bb.7:
+ ; GCN: SI_SPILL_V128_SAVE %{{[0-9]+}}, %stack.1, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr5, 0, implicit $exec
+
undef %15.sub0:vreg_128 = V_MOV_B32_e32 0, implicit $exec
%15.sub1:vreg_128 = COPY %15.sub0
%15.sub2:vreg_128 = COPY %15.sub0
@@ -114,6 +121,10 @@ body: |
bb.9:
successors: %bb.12(0x80000000)
+
+ ; GCN-LABEL: bb.9:
+ ; GCN: SI_SPILL_V128_SAVE %{{[0-9]+}}, %stack.1, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr5, 0, implicit $exec
+
undef %15.sub0:vreg_128 = V_MOV_B32_e32 0, implicit $exec
%15.sub1:vreg_128 = COPY %15.sub0
%15.sub2:vreg_128 = COPY %15.sub0
@@ -121,6 +132,10 @@ body: |
bb.10:
successors: %bb.12(0x80000000)
+
+ ; GCN-LABEL: bb.10:
+ ; GCN: SI_SPILL_V128_SAVE %{{[0-9]+}}, %stack.1, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr5, 0, implicit $exec
+
undef %15.sub0:vreg_128 = V_MOV_B32_e32 2143289344, implicit $exec
%15.sub1:vreg_128 = COPY %15.sub0
%15.sub2:vreg_128 = COPY %15.sub0
@@ -143,12 +158,6 @@ body: |
bb.13:
successors: %bb.15(0x40000000), %bb.14(0x40000000)
- ; In reality we are checking that this code doesn't assert when splitting
- ; and inserting a spill. Here we just check that the point where the error
- ; occurs we see a correctly generated spill.
- ; GCN-LABEL: bb.13:
- ; GCN: SI_SPILL_V128_SAVE %{{[0-9]+}}, %stack.1, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr5, 0, implicit $exec
-
%18:vgpr_32 = V_MAD_F32 0, %10.sub0, 0, target-flags(amdgpu-gotprel) 1073741824, 0, -1082130432, 0, 0, implicit $exec
%19:vgpr_32 = V_MAD_F32 0, %12.sub0, 0, target-flags(amdgpu-gotprel) 0, 0, 0, 0, 0, implicit $exec
%20:sreg_128 = S_BUFFER_LOAD_DWORDX4_IMM undef %21:sreg_128, 1040, 0 :: (dereferenceable invariant load 16)
Added: llvm/trunk/test/CodeGen/Thumb/ragreedy-implicit-def.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb/ragreedy-implicit-def.ll?rev=349151&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb/ragreedy-implicit-def.ll (added)
+++ llvm/trunk/test/CodeGen/Thumb/ragreedy-implicit-def.ll Fri Dec 14 06:07:57 2018
@@ -0,0 +1,99 @@
+; REQUIRES: asserts
+; RUN: llc -mtriple=thumbv6m -regalloc=greedy -stats < %s 2>&1 | FileCheck %s
+
+; Undef incoming values to phis end up creating IMPLICIT_DEF values. If we don't
+; prefer them to be in a register then we get fewer spilled live ranges (6
+; compared to 7).
+; CHECK: 6 regalloc - Number of spilled live ranges
+
+declare i32 @otherfn(i32)
+define void @fn(i32 %val, i32* %ptr) {
+entry:
+ %gep1 = getelementptr i32, i32* %ptr, i32 0
+ %gep2 = getelementptr i32, i32* %ptr, i32 1
+ %gep3 = getelementptr i32, i32* %ptr, i32 2
+ %gep4 = getelementptr i32, i32* %ptr, i32 3
+ %gep5 = getelementptr i32, i32* %ptr, i32 4
+ %gep6 = getelementptr i32, i32* %ptr, i32 5
+ %gep7 = getelementptr i32, i32* %ptr, i32 6
+ %gep8 = getelementptr i32, i32* %ptr, i32 7
+ %cmp1 = icmp uge i32 %val, 3
+ br i1 %cmp1, label %if, label %then
+
+if:
+ %val1 = load i32, i32* %gep1, align 4
+ %val2 = load i32, i32* %gep2, align 4
+ %val3 = load i32, i32* %gep3, align 4
+ %val4 = load i32, i32* %gep4, align 4
+ %val5 = load i32, i32* %gep5, align 4
+ %val6 = load i32, i32* %gep6, align 4
+ %val7 = load i32, i32* %gep7, align 4
+ %val8 = load i32, i32* %gep8, align 4
+ br label %then
+
+then:
+ %phi1a = phi i32 [ %val1, %if ], [ undef, %entry ]
+ %phi2a = phi i32 [ %val2, %if ], [ undef, %entry ]
+ %phi3a = phi i32 [ %val3, %if ], [ undef, %entry ]
+ %phi4a = phi i32 [ %val4, %if ], [ undef, %entry ]
+ %phi5a = phi i32 [ %val5, %if ], [ undef, %entry ]
+ %phi6a = phi i32 [ %val6, %if ], [ undef, %entry ]
+ %phi7a = phi i32 [ %val7, %if ], [ undef, %entry ]
+ %phi8a = phi i32 [ %val8, %if ], [ undef, %entry ]
+ %switchval = call i32 @otherfn(i32 %val)
+ switch i32 %switchval, label %default [
+ i32 0, label %case0
+ i32 1, label %case1
+ i32 5, label %case5
+ i32 6, label %case6
+ i32 7, label %case7
+ i32 8, label %case8
+ ]
+
+default:
+ br label %switchend
+
+case0:
+ br label %switchend
+
+case1:
+ br label %switchend
+
+case5:
+ br label %switchend
+
+case6:
+ br label %switchend
+
+case7:
+ br label %switchend
+
+case8:
+ br label %switchend
+
+switchend:
+ %phi1b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi1a, %case5 ], [ 1, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi2b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi2a, %case5 ], [ 2, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi3b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi3a, %case5 ], [ 3, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi4b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi4a, %case5 ], [ 4, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi5b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi5a, %case5 ], [ 5, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi6b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi6a, %case5 ], [ 6, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi7b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi7a, %case5 ], [ 7, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %phi8b = phi i32 [ 0, %default ], [ undef, %case0 ], [ undef, %case1 ], [ %phi8a, %case5 ], [ 8, %case6 ], [ 2, %case7 ], [ 1, %case8 ]
+ %cmp2 = icmp uge i32 %val, 4
+ br i1 %cmp2, label %if2, label %end
+
+if2:
+ store i32 %phi1b, i32* %gep1, align 4
+ store i32 %phi2b, i32* %gep2, align 4
+ store i32 %phi3b, i32* %gep3, align 4
+ store i32 %phi4b, i32* %gep4, align 4
+ store i32 %phi5b, i32* %gep5, align 4
+ store i32 %phi6b, i32* %gep6, align 4
+ store i32 %phi7b, i32* %gep7, align 4
+ store i32 %phi8b, i32* %gep8, align 4
+ br label %end
+
+end:
+ ret void
+}
Modified: llvm/trunk/test/CodeGen/X86/pr38795.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr38795.ll?rev=349151&r1=349150&r2=349151&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/pr38795.ll (original)
+++ llvm/trunk/test/CodeGen/X86/pr38795.ll Fri Dec 14 06:07:57 2018
@@ -24,22 +24,23 @@ define dso_local void @fn() {
; CHECK-NEXT: .cfi_offset %ebx, -12
; CHECK-NEXT: .cfi_offset %ebp, -8
; CHECK-NEXT: xorl %ebx, %ebx
-; CHECK-NEXT: # implicit-def: $esi
+; CHECK-NEXT: # implicit-def: $ecx
; CHECK-NEXT: # implicit-def: $edi
-; CHECK-NEXT: # implicit-def: $ah
; CHECK-NEXT: # implicit-def: $al
-; CHECK-NEXT: # implicit-def: $edx
+; CHECK-NEXT: # kill: killed $al
+; CHECK-NEXT: # implicit-def: $dl
+; CHECK-NEXT: # implicit-def: $ebp
; CHECK-NEXT: jmp .LBB0_1
; CHECK-NEXT: .p2align 4, 0x90
; CHECK-NEXT: .LBB0_16: # %for.inc
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %ah # 1-byte Reload
-; CHECK-NEXT: movb %cl, %al
+; CHECK-NEXT: movb %dl, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
+; CHECK-NEXT: movb %dh, %dl
; CHECK-NEXT: .LBB0_1: # %for.cond
; CHECK-NEXT: # =>This Loop Header: Depth=1
; CHECK-NEXT: # Child Loop BB0_20 Depth 2
-; CHECK-NEXT: cmpb $8, %al
-; CHECK-NEXT: movb %al, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
+; CHECK-NEXT: cmpb $8, %dl
+; CHECK-NEXT: movb %dl, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
; CHECK-NEXT: ja .LBB0_3
; CHECK-NEXT: # %bb.2: # %for.cond
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
@@ -47,28 +48,27 @@ define dso_local void @fn() {
; CHECK-NEXT: je .LBB0_3
; CHECK-NEXT: # %bb.4: # %if.end
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: movl %edx, %ebp
-; CHECK-NEXT: movl %esi, %ecx
-; CHECK-NEXT: movl %esi, %eax
+; CHECK-NEXT: movl %ecx, %eax
; CHECK-NEXT: cltd
; CHECK-NEXT: idivl a
-; CHECK-NEXT: movl %eax, %esi
-; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %al # 1-byte Reload
-; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
+; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %dl # 1-byte Reload
+; CHECK-NEXT: movb %cl, %dh
; CHECK-NEXT: movl $0, h
-; CHECK-NEXT: cmpb $8, %al
+; CHECK-NEXT: cmpb $8, %dl
; CHECK-NEXT: jg .LBB0_8
; CHECK-NEXT: # %bb.5: # %if.then13
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT: movl %eax, %esi
; CHECK-NEXT: movl $.str, (%esp)
-; CHECK-NEXT: movb %cl, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
+; CHECK-NEXT: movb %dh, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
; CHECK-NEXT: calll printf
-; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %cl # 1-byte Reload
+; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %dh # 1-byte Reload
; CHECK-NEXT: testb %bl, %bl
+; CHECK-NEXT: movl %esi, %ecx
; CHECK-NEXT: # implicit-def: $eax
-; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %ch # 1-byte Reload
-; CHECK-NEXT: movb %cl, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
-; CHECK-NEXT: movl %ebp, %edx
+; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %dl # 1-byte Reload
+; CHECK-NEXT: movb %dl, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
+; CHECK-NEXT: movb %dh, %dl
; CHECK-NEXT: jne .LBB0_16
; CHECK-NEXT: .p2align 4, 0x90
; CHECK-NEXT: # %bb.6: # %for.cond35
@@ -91,19 +91,16 @@ define dso_local void @fn() {
; CHECK-NEXT: calll printf
; CHECK-NEXT: .LBB0_19: # %for.end46
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: # implicit-def: $ch
-; CHECK-NEXT: # implicit-def: $cl
-; CHECK-NEXT: # implicit-def: $edx
+; CHECK-NEXT: # implicit-def: $dl
+; CHECK-NEXT: # implicit-def: $dh
+; CHECK-NEXT: # implicit-def: $ebp
; CHECK-NEXT: jmp .LBB0_20
; CHECK-NEXT: .p2align 4, 0x90
; CHECK-NEXT: .LBB0_3: # %if.then
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
; CHECK-NEXT: movl $.str, (%esp)
-; CHECK-NEXT: movl %edx, %esi
-; CHECK-NEXT: movb %ah, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
; CHECK-NEXT: calll printf
-; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %ch # 1-byte Reload
-; CHECK-NEXT: movl %esi, %edx
+; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %dl # 1-byte Reload
; CHECK-NEXT: # implicit-def: $eax
; CHECK-NEXT: testl %edi, %edi
; CHECK-NEXT: jne .LBB0_11
@@ -111,25 +108,15 @@ define dso_local void @fn() {
; CHECK-NEXT: .p2align 4, 0x90
; CHECK-NEXT: .LBB0_8: # %if.end21
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: # implicit-def: $edx
+; CHECK-NEXT: # implicit-def: $ebp
; CHECK-NEXT: testb %bl, %bl
; CHECK-NEXT: je .LBB0_13
+; CHECK-NEXT: jmp .LBB0_10
; CHECK-NEXT: .p2align 4, 0x90
-; CHECK-NEXT: .LBB0_10: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: # implicit-def: $eax
-; CHECK-NEXT: testb %bl, %bl
-; CHECK-NEXT: je .LBB0_17
-; CHECK-NEXT: .LBB0_12: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: # implicit-def: $edi
-; CHECK-NEXT: # implicit-def: $ch
-; CHECK-NEXT: # implicit-def: $cl
-; CHECK-NEXT: # kill: killed $cl
-; CHECK-NEXT: # implicit-def: $edx
-; CHECK-NEXT: testl %edi, %edi
-; CHECK-NEXT: jne .LBB0_11
; CHECK-NEXT: .LBB0_7: # in Loop: Header=BB0_1 Depth=1
; CHECK-NEXT: xorl %edi, %edi
-; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %cl # 1-byte Reload
+; CHECK-NEXT: movb %dl, %dh
+; CHECK-NEXT: movb {{[-0-9]+}}(%e{{[sb]}}p), %dl # 1-byte Reload
; CHECK-NEXT: .p2align 4, 0x90
; CHECK-NEXT: .LBB0_20: # %for.cond47
; CHECK-NEXT: # Parent Loop BB0_1 Depth=1
@@ -140,25 +127,38 @@ define dso_local void @fn() {
; CHECK-NEXT: # in Loop: Header=BB0_20 Depth=2
; CHECK-NEXT: testb %bl, %bl
; CHECK-NEXT: jne .LBB0_20
-; CHECK-NEXT: # %bb.22: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: movb %ch, %al
+; CHECK-NEXT: # %bb.9: # %ae
+; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
; CHECK-NEXT: testb %bl, %bl
; CHECK-NEXT: jne .LBB0_10
; CHECK-NEXT: .LBB0_13: # %if.end26
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: xorl %esi, %esi
-; CHECK-NEXT: testb %al, %al
-; CHECK-NEXT: movb %al, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
+; CHECK-NEXT: xorl %ecx, %ecx
+; CHECK-NEXT: testb %dl, %dl
; CHECK-NEXT: je .LBB0_16
; CHECK-NEXT: # %bb.14: # %if.end26
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: testl %edx, %edx
+; CHECK-NEXT: testl %ebp, %ebp
; CHECK-NEXT: jne .LBB0_16
; CHECK-NEXT: # %bb.15: # %if.then31
; CHECK-NEXT: # in Loop: Header=BB0_1 Depth=1
-; CHECK-NEXT: xorl %esi, %esi
-; CHECK-NEXT: xorl %edx, %edx
+; CHECK-NEXT: xorl %ecx, %ecx
+; CHECK-NEXT: xorl %ebp, %ebp
; CHECK-NEXT: jmp .LBB0_16
+; CHECK-NEXT: .p2align 4, 0x90
+; CHECK-NEXT: .LBB0_10: # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT: # implicit-def: $eax
+; CHECK-NEXT: testb %bl, %bl
+; CHECK-NEXT: je .LBB0_17
+; CHECK-NEXT: .LBB0_12: # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT: # implicit-def: $edi
+; CHECK-NEXT: # implicit-def: $cl
+; CHECK-NEXT: # kill: killed $cl
+; CHECK-NEXT: # implicit-def: $dl
+; CHECK-NEXT: # implicit-def: $ebp
+; CHECK-NEXT: testl %edi, %edi
+; CHECK-NEXT: jne .LBB0_11
+; CHECK-NEXT: jmp .LBB0_7
entry:
br label %for.cond
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