[llvm-commits] [llvm] r79338 - in /llvm/trunk: lib/CodeGen/BranchFolding.cpp test/CodeGen/Thumb2/thumb2-ifcvt2.ll test/CodeGen/X86/2009-08-06-branchfolder-crash.ll test/CodeGen/X86/omit-label.ll
Dan Gohman
gohman at apple.com
Tue Aug 18 08:18:18 PDT 2009
Author: djg
Date: Tue Aug 18 10:18:18 2009
New Revision: 79338
URL: http://llvm.org/viewvc/llvm-project?rev=79338&view=rev
Log:
Make tail merging handle blocks with repeated predecessors correctly, and
remove RemoveDuplicateSuccessor, as it is no longer necessary, and because
it breaks assumptions made in
MachineBasicBlock::isOnlyReachableByFallthrough.
Convert test/CodeGen/X86/omit-label.ll to FileCheck and add a testcase
for PR4732.
test/CodeGen/Thumb2/thumb2-ifcvt2.ll sees a diff with this commit due to
it being bugpoint-reduced to the point where it doesn't matter what the
condition for the branch is.
Add some more interesting code to
test/CodeGen/X86/2009-08-06-branchfolder-crash.ll, which is the testcase
that originally motivated the RemoveDuplicateSuccessor code, to help
verify that the original problem isn't being re-broken.
Modified:
llvm/trunk/lib/CodeGen/BranchFolding.cpp
llvm/trunk/test/CodeGen/Thumb2/thumb2-ifcvt2.ll
llvm/trunk/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
llvm/trunk/test/CodeGen/X86/omit-label.ll
Modified: llvm/trunk/lib/CodeGen/BranchFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/BranchFolding.cpp?rev=79338&r1=79337&r2=79338&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/BranchFolding.cpp (original)
+++ llvm/trunk/lib/CodeGen/BranchFolding.cpp Tue Aug 18 10:18:18 2009
@@ -700,6 +700,7 @@
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
if (I->pred_size() >= 2 && I->pred_size() < TailMergeThreshold) {
+ SmallPtrSet<MachineBasicBlock *, 8> UniquePreds;
MachineBasicBlock *IBB = I;
MachineBasicBlock *PredBB = prior(I);
MergePotentials.clear();
@@ -710,6 +711,9 @@
// Skip blocks that loop to themselves, can't tail merge these.
if (PBB==IBB)
continue;
+ // Visit each predecessor only once.
+ if (!UniquePreds.insert(PBB))
+ continue;
MachineBasicBlock *TBB = 0, *FBB = 0;
SmallVector<MachineOperand, 4> Cond;
if (!TII->AnalyzeBranch(*PBB, TBB, FBB, Cond, true)) {
@@ -850,27 +854,6 @@
return CanFallThrough(CurBB, CurUnAnalyzable, TBB, FBB, Cond);
}
-/// RemoveDuplicateSuccessor - make sure block Pred has at most one
-/// successor edge leading to Succ. This is only called in one place,
-/// but Chris prefers that it be a separate function.
-static void RemoveDuplicateSuccessor(MachineBasicBlock *Pred,
- MachineBasicBlock *Succ) {
- MachineBasicBlock::succ_iterator SI = Pred->succ_begin();
- bool found = false;
- while (SI != Pred->succ_end()) {
- if (*SI == Succ) {
- if (!found) {
- found = true;
- ++SI;
- } else {
- SI = Pred->removeSuccessor(SI);
- }
- } else {
- ++SI;
- }
- }
-}
-
/// IsBetterFallthrough - Return true if it would be clearly better to
/// fall-through to MBB1 than to fall through into MBB2. This has to return
/// a strict ordering, returning true for both (MBB1,MBB2) and (MBB2,MBB1) will
@@ -914,10 +897,6 @@
while (!MBB->pred_empty()) {
MachineBasicBlock *Pred = *(MBB->pred_end()-1);
Pred->ReplaceUsesOfBlockWith(MBB, FallThrough);
- // If this resulted in a predecessor with true and false edges
- // both going to the fallthrough block, clean up;
- // BranchFolding doesn't like this.
- RemoveDuplicateSuccessor(Pred, FallThrough);
}
// If MBB was the target of a jump table, update jump tables to go to the
// fallthrough instead.
Modified: llvm/trunk/test/CodeGen/Thumb2/thumb2-ifcvt2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb2/thumb2-ifcvt2.ll?rev=79338&r1=79337&r2=79338&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb2/thumb2-ifcvt2.ll (original)
+++ llvm/trunk/test/CodeGen/Thumb2/thumb2-ifcvt2.ll Tue Aug 18 10:18:18 2009
@@ -82,7 +82,7 @@
entry:
; CHECK: t2:
; CHECK: cmp r0, #0
-; CHECK: bne.n
+; CHECK: beq.n
br i1 undef, label %bb.i.i3, label %growMapping.exit
bb.i.i3: ; preds = %entry
Modified: llvm/trunk/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll?rev=79338&r1=79337&r2=79338&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll (original)
+++ llvm/trunk/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll Tue Aug 18 10:18:18 2009
@@ -88,3 +88,55 @@
}
declare i32 @safe()
+
+define i32 @func_35(i8 signext %p_35) nounwind readonly {
+entry:
+ %tobool = icmp eq i8 %p_35, 0 ; <i1> [#uses=1]
+ br i1 %tobool, label %lor.lhs.false, label %if.then
+
+lor.lhs.false: ; preds = %entry
+ %tmp1 = load i8* @g_3 ; <i8> [#uses=1]
+ %tobool3 = icmp eq i8 %tmp1, 0 ; <i1> [#uses=1]
+ br i1 %tobool3, label %return, label %if.then
+
+if.then: ; preds = %lor.lhs.false, %entry
+ %tmp4 = load i8* @g_3 ; <i8> [#uses=1]
+ %conv5 = sext i8 %tmp4 to i32 ; <i32> [#uses=1]
+ ret i32 %conv5
+
+return: ; preds = %lor.lhs.false
+ ret i32 0
+}
+
+define void @bar(i32 %p_5) noreturn nounwind {
+entry:
+ %cmp = icmp sgt i32 %p_5, 0 ; <i1> [#uses=2]
+ %call = tail call i32 @safe() nounwind ; <i32> [#uses=1]
+ %conv1 = trunc i32 %call to i8 ; <i8> [#uses=3]
+ %tobool.i = xor i1 %cmp, true ; <i1> [#uses=3]
+ %cmp.i = icmp sgt i8 %conv1, 0 ; <i1> [#uses=3]
+ %or.cond.i = or i1 %cmp.i, %tobool.i ; <i1> [#uses=1]
+ br i1 %or.cond.i, label %lor.rhs.i, label %land.lhs.true3.i
+
+land.lhs.true3.i: ; preds = %entry
+ %xor = zext i1 %cmp to i32 ; <i32> [#uses=1]
+ %conv5.i = sext i8 %conv1 to i32 ; <i32> [#uses=1]
+ %cmp7.i = icmp slt i32 %conv5.i, %xor ; <i1> [#uses=1]
+ %cmp7.i.not = xor i1 %cmp7.i, true ; <i1> [#uses=1]
+ %or.cond23.i = and i1 %cmp.i, %tobool.i ; <i1> [#uses=1]
+ %or.cond = and i1 %cmp7.i.not, %or.cond23.i ; <i1> [#uses=1]
+ br i1 %or.cond, label %lor.end.i, label %for.inc
+
+lor.rhs.i: ; preds = %entry
+ %or.cond23.i.old = and i1 %cmp.i, %tobool.i ; <i1> [#uses=1]
+ br i1 %or.cond23.i.old, label %lor.end.i, label %for.inc
+
+lor.end.i: ; preds = %lor.rhs.i, %land.lhs.true3.i
+ %tobool19.i = icmp eq i8 %conv1, 0 ; <i1> [#uses=0]
+ br label %for.inc
+
+for.inc: ; preds = %for.inc, %lor.end.i, %lor.rhs.i, %land.lhs.true3.i
+ br label %for.inc
+}
+
+declare i32 @safe()
Modified: llvm/trunk/test/CodeGen/X86/omit-label.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/omit-label.ll?rev=79338&r1=79337&r2=79338&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/omit-label.ll (original)
+++ llvm/trunk/test/CodeGen/X86/omit-label.ll Tue Aug 18 10:18:18 2009
@@ -1,7 +1,11 @@
-; RUN: llvm-as < %s | llc -march=x86-64 | grep BB1_1:
+; RUN: llvm-as < %s | llc -march=x86-64 -asm-verbose=false | FileCheck %s
; PR4126
+; PR4732
-; Don't omit this label's definition.
+; Don't omit these labels' definitions.
+
+; CHECK: bux:
+; CHECK: .LBB1_1:
define void @bux(i32 %p_53) nounwind optsize {
entry:
@@ -21,3 +25,33 @@
}
declare i32 @baz(...)
+
+; Don't omit this label in the assembly output.
+; CHECK: int321:
+; CHECK: jne .LBB2_1
+; CHECK: jle .LBB2_1
+; CHECK: .LBB2_1:
+
+define void @int321(i8 signext %p_103, i32 %uint8p_104) nounwind readnone {
+entry:
+ %tobool = icmp eq i8 %p_103, 0 ; <i1> [#uses=1]
+ %cmp.i = icmp sgt i8 %p_103, 0 ; <i1> [#uses=1]
+ %or.cond = and i1 %tobool, %cmp.i ; <i1> [#uses=1]
+ br i1 %or.cond, label %land.end.i, label %for.cond.preheader
+
+land.end.i: ; preds = %entry
+ %conv3.i = sext i8 %p_103 to i32 ; <i32> [#uses=1]
+ %div.i = sdiv i32 1, %conv3.i ; <i32> [#uses=1]
+ %tobool.i = icmp eq i32 %div.i, -2147483647 ; <i1> [#uses=0]
+ br label %for.cond.preheader
+
+for.cond.preheader: ; preds = %land.end.i, %entry
+ %cmp = icmp sgt i8 %p_103, 1 ; <i1> [#uses=1]
+ br i1 %cmp, label %for.end.split, label %for.cond
+
+for.cond: ; preds = %for.cond.preheader, %for.cond
+ br label %for.cond
+
+for.end.split: ; preds = %for.cond.preheader
+ ret void
+}
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