Fix PR 4626, a crash in branch folding after OptimizeBlock
produced a CFG it wasn't prepared for.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78351 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 193bbb6..d25152b 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -893,8 +893,24 @@
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.
+ MachineBasicBlock::succ_iterator SI = Pred->succ_begin();
+ bool found = false;
+ while (SI != Pred->succ_end()) {
+ if (*SI == FallThrough) {
+ if (!found) {
+ found = true;
+ ++SI;
+ } else {
+ SI = Pred->removeSuccessor(SI);
+ }
+ } else {
+ ++SI;
+ }
+ }
}
-
// If MBB was the target of a jump table, update jump tables to go to the
// fallthrough instead.
MBB->getParent()->getJumpTableInfo()->
diff --git a/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll b/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
new file mode 100644
index 0000000..5e58725
--- /dev/null
+++ b/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
@@ -0,0 +1,90 @@
+; RUN: llvm-as < %s | llc -O3
+; PR4626
+; ModuleID = '<stdin>'
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i386-pc-linux-gnu"
+@g_3 = common global i8 0, align 1 ; <i8*> [#uses=2]
+
+define signext i8 @safe_mul_func_int16_t_s_s(i32 %_si1, i8 signext %_si2) nounwind readnone {
+entry:
+ %tobool = icmp eq i32 %_si1, 0 ; <i1> [#uses=1]
+ %cmp = icmp sgt i8 %_si2, 0 ; <i1> [#uses=2]
+ %or.cond = or i1 %cmp, %tobool ; <i1> [#uses=1]
+ br i1 %or.cond, label %lor.rhs, label %land.lhs.true3
+
+land.lhs.true3: ; preds = %entry
+ %conv5 = sext i8 %_si2 to i32 ; <i32> [#uses=1]
+ %cmp7 = icmp slt i32 %conv5, %_si1 ; <i1> [#uses=1]
+ br i1 %cmp7, label %cond.end, label %lor.rhs
+
+lor.rhs: ; preds = %land.lhs.true3, %entry
+ %cmp10.not = icmp slt i32 %_si1, 1 ; <i1> [#uses=1]
+ %or.cond23 = and i1 %cmp, %cmp10.not ; <i1> [#uses=1]
+ br i1 %or.cond23, label %lor.end, label %cond.false
+
+lor.end: ; preds = %lor.rhs
+ %tobool19 = icmp ne i8 %_si2, 0 ; <i1> [#uses=2]
+ %lor.ext = zext i1 %tobool19 to i32 ; <i32> [#uses=1]
+ br i1 %tobool19, label %cond.end, label %cond.false
+
+cond.false: ; preds = %lor.end, %lor.rhs
+ %conv21 = sext i8 %_si2 to i32 ; <i32> [#uses=1]
+ br label %cond.end
+
+cond.end: ; preds = %cond.false, %lor.end, %land.lhs.true3
+ %cond = phi i32 [ %conv21, %cond.false ], [ 1, %land.lhs.true3 ], [ %lor.ext, %lor.end ] ; <i32> [#uses=1]
+ %conv22 = trunc i32 %cond to i8 ; <i8> [#uses=1]
+ ret i8 %conv22
+}
+
+define i32 @func_34(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 @foo(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()