From 6b843448d0f5a41e46a360aed7bc0e68af54723d Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Mon, 17 Jun 2019 07:47:28 +0000 Subject: [PATCH] Re-commit r357452 (take 3): "SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)" Third time's the charm. This was reverted in r363220 due to being suspected of an internal benchmark regression and a test failure, none of which turned out to be caused by this. llvm-svn: 363529 --- lib/Transforms/Utils/SimplifyCFG.cpp | 29 +++++------ test/CodeGen/AArch64/max-jump-table.ll | 48 +++++++++--------- test/CodeGen/AArch64/min-jump-table.ll | 30 +++++------ test/CodeGen/AArch64/win64-jumptable.ll | 50 +++++++++---------- test/CodeGen/ARM/cmpxchg-idioms.ll | 4 +- .../SimplifyCFG/sink-common-code.ll | 44 ++++++++++++++++ 6 files changed, 125 insertions(+), 80 deletions(-) diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index a8d24378279..f571aa6bf2e 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1445,9 +1445,10 @@ HoistTerminator: static bool canSinkInstructions( ArrayRef Insts, DenseMap> &PHIOperands) { - // Prune out obviously bad instructions to move. Any non-store instruction - // must have exactly one use, and we check later that use is by a single, - // common PHI instruction in the successor. + // Prune out obviously bad instructions to move. Each instruction must have + // exactly zero or one use, and we check later that use is by a single, common + // PHI instruction in the successor. + bool HasUse = !Insts.front()->user_empty(); for (auto *I : Insts) { // These instructions may change or break semantics if moved. if (isa(I) || I->isEHPad() || isa(I) || @@ -1461,9 +1462,10 @@ static bool canSinkInstructions( if (C->isInlineAsm()) return false; - // Everything must have only one use too, apart from stores which - // have no uses. - if (!isa(I) && !I->hasOneUse()) + // Each instruction must have zero or one use. + if (HasUse && !I->hasOneUse()) + return false; + if (!HasUse && !I->user_empty()) return false; } @@ -1472,11 +1474,11 @@ static bool canSinkInstructions( if (!I->isSameOperationAs(I0)) return false; - // All instructions in Insts are known to be the same opcode. If they aren't - // stores, check the only user of each is a PHI or in the same block as the - // instruction, because if a user is in the same block as an instruction - // we're contemplating sinking, it must already be determined to be sinkable. - if (!isa(I0)) { + // All instructions in Insts are known to be the same opcode. If they have a + // use, check that the only user is a PHI or in the same block as the + // instruction, because if a user is in the same block as an instruction we're + // contemplating sinking, it must already be determined to be sinkable. + if (HasUse) { auto *PNUse = dyn_cast(*I0->user_begin()); auto *Succ = I0->getParent()->getTerminator()->getSuccessor(0); if (!all_of(Insts, [&PNUse,&Succ](const Instruction *I) -> bool { @@ -1554,7 +1556,7 @@ static bool sinkLastInstruction(ArrayRef Blocks) { // it is slightly over-aggressive - it gets confused by commutative instructions // so double-check it here. Instruction *I0 = Insts.front(); - if (!isa(I0)) { + if (!I0->user_empty()) { auto *PNUse = dyn_cast(*I0->user_begin()); if (!all_of(Insts, [&PNUse](const Instruction *I) -> bool { auto *U = cast(*I->user_begin()); @@ -1612,11 +1614,10 @@ static bool sinkLastInstruction(ArrayRef Blocks) { I0->andIRFlags(I); } - if (!isa(I0)) { + if (!I0->user_empty()) { // canSinkLastInstruction checked that all instructions were used by // one and only one PHI node. Find that now, RAUW it to our common // instruction and nuke it. - assert(I0->hasOneUse()); auto *PN = cast(*I0->user_begin()); PN->replaceAllUsesWith(I0); PN->eraseFromParent(); diff --git a/test/CodeGen/AArch64/max-jump-table.ll b/test/CodeGen/AArch64/max-jump-table.ll index 44dde7b1cd0..f309efe95b5 100644 --- a/test/CodeGen/AArch64/max-jump-table.ll +++ b/test/CodeGen/AArch64/max-jump-table.ll @@ -4,7 +4,7 @@ ; RUN: llc %s -O2 -print-machineinstrs -mtriple=aarch64-linux-gnu -jump-table-density=40 -mcpu=exynos-m1 -o /dev/null 2> %t; FileCheck %s --check-prefixes=CHECK,CHECKM1 < %t ; RUN: llc %s -O2 -print-machineinstrs -mtriple=aarch64-linux-gnu -jump-table-density=40 -mcpu=exynos-m3 -o /dev/null 2> %t; FileCheck %s --check-prefixes=CHECK,CHECKM3 < %t -declare void @ext(i32) +declare void @ext(i32, i32) define i32 @jt1(i32 %a, i32 %b) { entry: @@ -45,23 +45,23 @@ entry: ; CHECKM3-NEXT: %jump-table.0: ; CHECKM3-NOT: %jump-table.1: -bb1: tail call void @ext(i32 0) br label %return -bb2: tail call void @ext(i32 2) br label %return -bb3: tail call void @ext(i32 4) br label %return -bb4: tail call void @ext(i32 6) br label %return -bb5: tail call void @ext(i32 8) br label %return -bb6: tail call void @ext(i32 10) br label %return -bb7: tail call void @ext(i32 12) br label %return -bb8: tail call void @ext(i32 14) br label %return -bb9: tail call void @ext(i32 16) br label %return -bb10: tail call void @ext(i32 18) br label %return -bb11: tail call void @ext(i32 20) br label %return -bb12: tail call void @ext(i32 22) br label %return -bb13: tail call void @ext(i32 24) br label %return -bb14: tail call void @ext(i32 26) br label %return -bb15: tail call void @ext(i32 28) br label %return -bb16: tail call void @ext(i32 30) br label %return -bb17: tail call void @ext(i32 32) br label %return +bb1: tail call void @ext(i32 1, i32 0) br label %return +bb2: tail call void @ext(i32 2, i32 2) br label %return +bb3: tail call void @ext(i32 3, i32 4) br label %return +bb4: tail call void @ext(i32 4, i32 6) br label %return +bb5: tail call void @ext(i32 5, i32 8) br label %return +bb6: tail call void @ext(i32 6, i32 10) br label %return +bb7: tail call void @ext(i32 7, i32 12) br label %return +bb8: tail call void @ext(i32 8, i32 14) br label %return +bb9: tail call void @ext(i32 9, i32 16) br label %return +bb10: tail call void @ext(i32 1, i32 18) br label %return +bb11: tail call void @ext(i32 2, i32 20) br label %return +bb12: tail call void @ext(i32 3, i32 22) br label %return +bb13: tail call void @ext(i32 4, i32 24) br label %return +bb14: tail call void @ext(i32 5, i32 26) br label %return +bb15: tail call void @ext(i32 6, i32 28) br label %return +bb16: tail call void @ext(i32 7, i32 30) br label %return +bb17: tail call void @ext(i32 8, i32 32) br label %return return: ret i32 %b } @@ -91,11 +91,11 @@ entry: ; CHECKM3-NOT: %jump-table.1 ; CHECK-DAG: End machine code for function jt2. -bb1: tail call void @ext(i32 1) br label %return -bb2: tail call void @ext(i32 2) br label %return -bb3: tail call void @ext(i32 3) br label %return -bb4: tail call void @ext(i32 4) br label %return -bb5: tail call void @ext(i32 5) br label %return -bb6: tail call void @ext(i32 6) br label %return +bb1: tail call void @ext(i32 6, i32 1) br label %return +bb2: tail call void @ext(i32 5, i32 2) br label %return +bb3: tail call void @ext(i32 4, i32 3) br label %return +bb4: tail call void @ext(i32 3, i32 4) br label %return +bb5: tail call void @ext(i32 2, i32 5) br label %return +bb6: tail call void @ext(i32 1, i32 6) br label %return return: ret void } diff --git a/test/CodeGen/AArch64/min-jump-table.ll b/test/CodeGen/AArch64/min-jump-table.ll index 7d6d26259af..8d16a4d9d6a 100644 --- a/test/CodeGen/AArch64/min-jump-table.ll +++ b/test/CodeGen/AArch64/min-jump-table.ll @@ -2,7 +2,7 @@ ; RUN: llc %s -O2 -print-machineinstrs -mtriple=aarch64-linux-gnu -jump-table-density=40 -min-jump-table-entries=4 -o /dev/null 2> %t; FileCheck %s --check-prefixes=CHECK,CHECK4 < %t ; RUN: llc %s -O2 -print-machineinstrs -mtriple=aarch64-linux-gnu -jump-table-density=40 -min-jump-table-entries=8 -o /dev/null 2> %t; FileCheck %s --check-prefixes=CHECK,CHECK8 < %t -declare void @ext(i32) +declare void @ext(i32, i32) define i32 @jt2(i32 %a, i32 %b) { entry: @@ -17,8 +17,8 @@ entry: ; CHECK4-NOT: {{^}}Jump Tables: ; CHECK8-NOT: {{^}}Jump Tables: -bb1: tail call void @ext(i32 0) br label %return -bb2: tail call void @ext(i32 2) br label %return +bb1: tail call void @ext(i32 1, i32 0) br label %return +bb2: tail call void @ext(i32 2, i32 2) br label %return return: ret i32 %b } @@ -40,10 +40,10 @@ entry: ; CHECK4-NOT: %jump-table.1: ; CHECK8-NOT: {{^}}Jump Tables: -bb1: tail call void @ext(i32 0) br label %return -bb2: tail call void @ext(i32 2) br label %return -bb3: tail call void @ext(i32 4) br label %return -bb4: tail call void @ext(i32 6) br label %return +bb1: tail call void @ext(i32 1, i32 0) br label %return +bb2: tail call void @ext(i32 3, i32 2) br label %return +bb3: tail call void @ext(i32 4, i32 4) br label %return +bb4: tail call void @ext(i32 5, i32 6) br label %return return: ret i32 %b } @@ -65,14 +65,14 @@ entry: ; CHECK-NEXT: %jump-table.0: ; CHECK-NOT: %jump-table.1: -bb1: tail call void @ext(i32 0) br label %return -bb2: tail call void @ext(i32 2) br label %return -bb3: tail call void @ext(i32 4) br label %return -bb4: tail call void @ext(i32 6) br label %return -bb5: tail call void @ext(i32 8) br label %return -bb6: tail call void @ext(i32 10) br label %return -bb7: tail call void @ext(i32 12) br label %return -bb8: tail call void @ext(i32 14) br label %return +bb1: tail call void @ext(i32 1, i32 0) br label %return +bb2: tail call void @ext(i32 2, i32 2) br label %return +bb3: tail call void @ext(i32 3, i32 4) br label %return +bb4: tail call void @ext(i32 4, i32 6) br label %return +bb5: tail call void @ext(i32 5, i32 8) br label %return +bb6: tail call void @ext(i32 6, i32 10) br label %return +bb7: tail call void @ext(i32 7, i32 12) br label %return +bb8: tail call void @ext(i32 8, i32 14) br label %return return: ret i32 %b } diff --git a/test/CodeGen/AArch64/win64-jumptable.ll b/test/CodeGen/AArch64/win64-jumptable.ll index 4eb86ea663f..6a9752687aa 100644 --- a/test/CodeGen/AArch64/win64-jumptable.ll +++ b/test/CodeGen/AArch64/win64-jumptable.ll @@ -10,43 +10,43 @@ entry: i32 3, label %sw.bb3 ] -sw.bb: ; preds = %entry - tail call void @g(i32 0) #2 +sw.bb: + tail call void @g(i32 0, i32 4) br label %sw.epilog -sw.bb1: ; preds = %entry - tail call void @g(i32 1) #2 +sw.bb1: + tail call void @g(i32 1, i32 5) br label %sw.epilog -sw.bb2: ; preds = %entry - tail call void @g(i32 2) #2 +sw.bb2: + tail call void @g(i32 2, i32 6) br label %sw.epilog -sw.bb3: ; preds = %entry - tail call void @g(i32 3) #2 +sw.bb3: + tail call void @g(i32 3, i32 7) br label %sw.epilog -sw.epilog: ; preds = %entry, %sw.bb3, %sw.bb2, %sw.bb1, %sw.bb - tail call void @g(i32 10) #2 +sw.epilog: + tail call void @g(i32 10, i32 8) ret void } -declare void @g(i32) +declare void @g(i32, i32) -; CHECK: .text -; CHECK: f: -; CHECK: .seh_proc f -; CHECK: b g -; CHECK-NEXT: .p2align 2 -; CHECK-NEXT: .LJTI0_0: -; CHECK: .word .LBB0_2-.LJTI0_0 -; CHECK: .word .LBB0_3-.LJTI0_0 -; CHECK: .word .LBB0_4-.LJTI0_0 -; CHECK: .word .LBB0_5-.LJTI0_0 -; CHECK: .section .xdata,"dr" -; CHECK: .seh_handlerdata -; CHECK: .text -; CHECK: .seh_endproc +; CHECK: .text +; CHECK: f: +; CHECK: .seh_proc f +; CHECK: b g +; CHECK-NEXT: .p2align 2 +; CHECK-NEXT: .LJTI0_0: +; CHECK: .word .LBB0_2-.LJTI0_0 +; CHECK: .word .LBB0_3-.LJTI0_0 +; CHECK: .word .LBB0_4-.LJTI0_0 +; CHECK: .word .LBB0_5-.LJTI0_0 +; CHECK: .section .xdata,"dr" +; CHECK: .seh_handlerdata +; CHECK: .text +; CHECK: .seh_endproc ; Check that we can emit an object file with correct unwind info. ; UNWIND: FunctionLength: {{[1-9][0-9]*}} diff --git a/test/CodeGen/ARM/cmpxchg-idioms.ll b/test/CodeGen/ARM/cmpxchg-idioms.ll index 283202f0cc1..1af80e7d0c8 100644 --- a/test/CodeGen/ARM/cmpxchg-idioms.ll +++ b/test/CodeGen/ARM/cmpxchg-idioms.ll @@ -20,14 +20,14 @@ define i32 @test_return(i32* %p, i32 %oldval, i32 %newval) { ; CHECK: [[FAILED]]: ; CHECK-NOT: cmp {{r[0-9]+}}, {{r[0-9]+}} ; CHECK: clrex -; CHECK: dmb ish ; CHECK: movs r0, #0 +; CHECK: dmb ish ; CHECK: bx lr ; CHECK: [[SUCCESS]]: ; CHECK-NOT: cmp {{r[0-9]+}}, {{r[0-9]+}} -; CHECK: dmb ish ; CHECK: movs r0, #1 +; CHECK: dmb ish ; CHECK: bx lr %pair = cmpxchg i32* %p, i32 %oldval, i32 %newval seq_cst seq_cst diff --git a/test/Transforms/SimplifyCFG/sink-common-code.ll b/test/Transforms/SimplifyCFG/sink-common-code.ll index 02c29bd3540..12a3e59cd37 100644 --- a/test/Transforms/SimplifyCFG/sink-common-code.ll +++ b/test/Transforms/SimplifyCFG/sink-common-code.ll @@ -843,6 +843,50 @@ if.end: ; CHECK: insertvalue ; CHECK-NOT: insertvalue + +declare void @baz(i32) + +define void @test_sink_void_calls(i32 %x) { +entry: + switch i32 %x, label %default [ + i32 0, label %bb0 + i32 1, label %bb1 + i32 2, label %bb2 + i32 3, label %bb3 + i32 4, label %bb4 + ] +bb0: + call void @baz(i32 12) + br label %return +bb1: + call void @baz(i32 34) + br label %return +bb2: + call void @baz(i32 56) + br label %return +bb3: + call void @baz(i32 78) + br label %return +bb4: + call void @baz(i32 90) + br label %return +default: + unreachable +return: + ret void + +; Check that the calls get sunk to the return block. +; We would previously not sink calls without uses, see PR41259. +; CHECK-LABEL: @test_sink_void_calls +; CHECK-NOT: call +; CHECK-LABEL: return: +; CHECK: phi +; CHECK: call +; CHECK-NOT: call +; CHECK: ret +} + + ; CHECK: ![[$TBAA]] = !{![[TYPE:[0-9]]], ![[TYPE]], i64 0} ; CHECK: ![[TYPE]] = !{!"float", ![[TEXT:[0-9]]]} ; CHECK: ![[TEXT]] = !{!"an example type tree"}