[llvm] r273700 - Codegen: Fix broken assumption in Tail Merge.
Kyle Butt via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 24 11:16:37 PDT 2016
Author: iteratee
Date: Fri Jun 24 13:16:36 2016
New Revision: 273700
URL: http://llvm.org/viewvc/llvm-project?rev=273700&view=rev
Log:
Codegen: Fix broken assumption in Tail Merge.
Tail merge was making the assumption that a layout successor or
predecessor was always a cfg successor/predecessor. Remove that
assumption. Changes to tests are necessary because the errant cfg edges
were preventing optimizations.
Added:
llvm/trunk/test/CodeGen/X86/tail-merge-unreachable.ll
Modified:
llvm/trunk/lib/CodeGen/BranchFolding.cpp
llvm/trunk/test/CodeGen/Mips/eh.ll
llvm/trunk/test/CodeGen/SPARC/missinglabel.ll
llvm/trunk/test/CodeGen/Thumb2/thumb2-cbnz.ll
llvm/trunk/test/CodeGen/Thumb2/v8_IT_5.ll
llvm/trunk/test/CodeGen/X86/br-fold.ll
Modified: llvm/trunk/lib/CodeGen/BranchFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/BranchFolding.cpp?rev=273700&r1=273699&r2=273700&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/BranchFolding.cpp (original)
+++ llvm/trunk/lib/CodeGen/BranchFolding.cpp Fri Jun 24 13:16:36 2016
@@ -1255,7 +1255,7 @@ ReoptimizeBlock:
// where a BB jumps to more than one landing pad.
// TODO: Is it ever worth rewriting predecessors which don't already
// jump to a landing pad, and so can safely jump to the fallthrough?
- } else {
+ } else if (MBB->isSuccessor(&*FallThrough)) {
// Rewrite all predecessors of the old block to go to the fallthrough
// instead.
while (!MBB->pred_empty()) {
Modified: llvm/trunk/test/CodeGen/Mips/eh.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/eh.ll?rev=273700&r1=273699&r2=273700&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Mips/eh.ll (original)
+++ llvm/trunk/test/CodeGen/Mips/eh.ll Fri Jun 24 13:16:36 2016
@@ -24,7 +24,7 @@ entry:
lpad: ; preds = %entry
; CHECK-EL: # %lpad
-; CHECK-EL: beq $5
+; CHECK-EL: bne $5
%exn.val = landingpad { i8*, i32 }
cleanup
Modified: llvm/trunk/test/CodeGen/SPARC/missinglabel.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/SPARC/missinglabel.ll?rev=273700&r1=273699&r2=273700&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/SPARC/missinglabel.ll (original)
+++ llvm/trunk/test/CodeGen/SPARC/missinglabel.ll Fri Jun 24 13:16:36 2016
@@ -4,14 +4,14 @@ target triple = "sparc64-unknown-linux-g
define void @f() align 2 {
entry:
-; CHECK: %xcc, .LBB0_1
+; CHECK: %xcc, .LBB0_2
%cmp = icmp eq i64 undef, 0
br i1 %cmp, label %targetblock, label %cond.false
cond.false:
unreachable
-; CHECK: .LBB0_1: ! %targetblock
+; CHECK: .LBB0_2: ! %targetblock
targetblock:
br i1 undef, label %cond.false.i83, label %exit.i85
Modified: llvm/trunk/test/CodeGen/Thumb2/thumb2-cbnz.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb2/thumb2-cbnz.ll?rev=273700&r1=273699&r2=273700&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb2/thumb2-cbnz.ll (original)
+++ llvm/trunk/test/CodeGen/Thumb2/thumb2-cbnz.ll Fri Jun 24 13:16:36 2016
@@ -5,6 +5,7 @@ declare double @foo(double) nounwind rea
define void @t(i32 %c, double %b) {
entry:
+; CHECK: cmp r0, #0
%cmp1 = icmp ne i32 %c, 0
br i1 %cmp1, label %bb3, label %bb1
@@ -23,8 +24,7 @@ bb7:
br i1 %cmp3, label %bb11, label %bb9
bb9: ; preds = %bb7
-; CHECK: cmp r0, #0
-; CHECK-NEXT: cbnz
+; CHECK: cbnz
%0 = tail call double @foo(double %b) nounwind readnone ; <double> [#uses=0]
br label %bb11
Modified: llvm/trunk/test/CodeGen/Thumb2/v8_IT_5.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb2/v8_IT_5.ll?rev=273700&r1=273699&r2=273700&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb2/v8_IT_5.ll (original)
+++ llvm/trunk/test/CodeGen/Thumb2/v8_IT_5.ll Fri Jun 24 13:16:36 2016
@@ -17,31 +17,13 @@
define i32 @t(i32 %type) optsize {
entry:
- br i1 undef, label %if.then, label %if.else
-
-if.then:
- unreachable
-
-if.else:
- br i1 undef, label %if.then15, label %if.else18
-
-if.then15:
- unreachable
-
-if.else18:
switch i32 %type, label %if.else173 [
- i32 3, label %if.then115
- i32 1, label %if.then102
+ i32 13, label %if.then115
+ i32 6, label %if.then102
]
if.then102:
- br i1 undef, label %cond.true10.i, label %t.exit
-
-cond.true10.i:
- br label %t.exit
-
-t.exit:
- unreachable
+ br label %if.then115
if.then115:
br i1 undef, label %if.else163, label %if.else145
@@ -62,4 +44,3 @@ if.else173:
}
declare hidden fastcc %struct.hc* @foo(%struct.hc* nocapture, i32) nounwind optsize
-
Modified: llvm/trunk/test/CodeGen/X86/br-fold.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/br-fold.ll?rev=273700&r1=273699&r2=273700&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/br-fold.ll (original)
+++ llvm/trunk/test/CodeGen/X86/br-fold.ll Fri Jun 24 13:16:36 2016
@@ -5,9 +5,11 @@
; RUN: llc -mtriple=x86_64-scei-ps4 < %s | FileCheck -check-prefix=PS4 %s
; X64_DARWIN: orq
+; X64_DARWIN-NEXT: jne
; X64_DARWIN-NEXT: %bb8.i329
; X64_LINUX: orq %rax, %rcx
+; X64_LINUX-NEXT: jne
; X64_LINUX-NEXT: %bb8.i329
; X64_WINDOWS: orq %rax, %rcx
Added: llvm/trunk/test/CodeGen/X86/tail-merge-unreachable.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/tail-merge-unreachable.ll?rev=273700&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/tail-merge-unreachable.ll (added)
+++ llvm/trunk/test/CodeGen/X86/tail-merge-unreachable.ll Fri Jun 24 13:16:36 2016
@@ -0,0 +1,34 @@
+; RUN: llc -mtriple=x86_64-linux-gnu %s -o - -verify-machineinstrs | FileCheck %s
+
+define i32 @tail_merge_unreachable(i32 %i) {
+entry:
+ br i1 undef, label %sw, label %end
+sw:
+ switch i32 %i, label %end [
+ i32 99, label %sw.bb
+ i32 98, label %sw.bb
+ i32 101, label %sw.bb
+ i32 97, label %sw.bb2
+ i32 96, label %sw.bb2
+ i32 100, label %sw.bb2
+ ]
+sw.bb:
+ unreachable
+sw.bb2:
+ unreachable
+end:
+ %p = phi i32 [ 1, %sw ], [ 0, %entry ]
+ ret i32 %p
+
+; CHECK-LABEL: tail_merge_unreachable:
+; Range Check
+; CHECK: addl $-96
+; CHECK: cmpl $5
+; CHECK: jbe [[JUMP_TABLE_BLOCK:[.][A-Za-z0-9_]+]]
+; CHECK: retq
+; CHECK: [[JUMP_TABLE_BLOCK]]:
+; CHECK: btl
+; CHECK: jae [[UNREACHABLE_BLOCK:[.][A-Za-z0-9_]+]]
+; CHECK [[UNREACHABLE_BLOCK]]:
+; CHECK: .Lfunc_end0
+}
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