[llvm] r217544 - [AlignmentFromAssumptions] Don't divide by zero for unknown starting alignment
Hal Finkel
hfinkel at anl.gov
Wed Sep 10 14:05:52 PDT 2014
Author: hfinkel
Date: Wed Sep 10 16:05:52 2014
New Revision: 217544
URL: http://llvm.org/viewvc/llvm-project?rev=217544&view=rev
Log:
[AlignmentFromAssumptions] Don't divide by zero for unknown starting alignment
The routine that determines an alignment given some SCEV returns zero if the
answer is unknown. In a case where we could determine the increment of an
AddRec but not the starting alignment, we would compute the integer modulus by
zero (which is illegal and traps). Prevent this by returning early if either
the start or increment alignment is unknown (zero).
Added:
llvm/trunk/test/Transforms/AlignmentFromAssumptions/start-unk.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp?rev=217544&r1=217543&r2=217544&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp Wed Sep 10 16:05:52 2014
@@ -179,7 +179,9 @@ static unsigned getNewAlignment(const SC
DEBUG(dbgs() << "\tnew start alignment: " << NewAlignment << "\n");
DEBUG(dbgs() << "\tnew inc alignment: " << NewIncAlignment << "\n");
- if (NewAlignment > NewIncAlignment) {
+ if (!NewAlignment || !NewIncAlignment) {
+ return 0;
+ } else if (NewAlignment > NewIncAlignment) {
if (NewAlignment % NewIncAlignment == 0) {
DEBUG(dbgs() << "\tnew start/inc alignment: " <<
NewIncAlignment << "\n");
@@ -191,7 +193,7 @@ static unsigned getNewAlignment(const SC
NewAlignment << "\n");
return NewAlignment;
}
- } else if (NewIncAlignment == NewAlignment && NewIncAlignment) {
+ } else if (NewIncAlignment == NewAlignment) {
DEBUG(dbgs() << "\tnew start/inc alignment: " <<
NewAlignment << "\n");
return NewAlignment;
Added: llvm/trunk/test/Transforms/AlignmentFromAssumptions/start-unk.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/AlignmentFromAssumptions/start-unk.ll?rev=217544&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/AlignmentFromAssumptions/start-unk.ll (added)
+++ llvm/trunk/test/Transforms/AlignmentFromAssumptions/start-unk.ll Wed Sep 10 16:05:52 2014
@@ -0,0 +1,154 @@
+; RUN: opt -alignment-from-assumptions -S < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%type1 = type { %type2 }
+%type2 = type { [4 x i8] }
+
+; Function Attrs: nounwind
+declare void @llvm.assume(i1) #0
+
+; Function Attrs: nounwind readnone
+declare i32 @llvm.bswap.i32(i32) #1
+
+; Function Attrs: nounwind uwtable
+define void @test1() unnamed_addr #2 align 2 {
+
+; CHECK-LABEL: @test1
+
+entry:
+ br i1 undef, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ unreachable
+
+if.end: ; preds = %entry
+ br i1 undef, label %return, label %if.end8
+
+if.end8: ; preds = %if.end
+ br i1 undef, label %if.then13, label %if.end14
+
+if.then13: ; preds = %if.end8
+ unreachable
+
+if.end14: ; preds = %if.end8
+ br i1 undef, label %cond.false.i129, label %cond.end.i136
+
+cond.false.i129: ; preds = %if.end14
+ unreachable
+
+cond.end.i136: ; preds = %if.end14
+ br i1 undef, label %land.lhs.true.i, label %if.end.i145
+
+land.lhs.true.i: ; preds = %cond.end.i136
+ br i1 undef, label %if.end.i145, label %if.then.i137
+
+if.then.i137: ; preds = %land.lhs.true.i
+ br i1 undef, label %cond.false8.i, label %cond.end9.i
+
+cond.false8.i: ; preds = %if.then.i137
+ unreachable
+
+cond.end9.i: ; preds = %if.then.i137
+ br i1 undef, label %if.then23, label %if.end24
+
+if.end.i145: ; preds = %land.lhs.true.i, %cond.end.i136
+ unreachable
+
+if.then23: ; preds = %cond.end9.i
+ unreachable
+
+if.end24: ; preds = %cond.end9.i
+ br i1 undef, label %for.end, label %for.body.lr.ph
+
+for.body.lr.ph: ; preds = %if.end24
+ unreachable
+
+for.end: ; preds = %if.end24
+ br i1 undef, label %if.end123, label %if.then121
+
+if.then121: ; preds = %for.end
+ unreachable
+
+if.end123: ; preds = %for.end
+ br i1 undef, label %if.end150, label %if.then126
+
+if.then126: ; preds = %if.end123
+ %ptrint.i.i185 = ptrtoint %type1* undef to i64
+ %maskedptr.i.i186 = and i64 %ptrint.i.i185, 1
+ %maskcond.i.i187 = icmp eq i64 %maskedptr.i.i186, 0
+ tail call void @llvm.assume(i1 %maskcond.i.i187) #0
+ %ret.0..sroa_cast.i.i188 = bitcast %type1* undef to i32*
+ %ret.0.copyload.i.i189 = load i32* %ret.0..sroa_cast.i.i188, align 2
+
+; CHECK: load {{.*}} align 2
+
+ %0 = tail call i32 @llvm.bswap.i32(i32 %ret.0.copyload.i.i189) #0
+ %conv131 = zext i32 %0 to i64
+ %add.ptr132 = getelementptr inbounds i8* undef, i64 %conv131
+ %1 = bitcast i8* %add.ptr132 to %type1*
+ br i1 undef, label %if.end150, label %if.end.i173
+
+if.end.i173: ; preds = %if.then126
+ br i1 undef, label %test1.exit, label %cond.false.i.i.i.i174
+
+cond.false.i.i.i.i174: ; preds = %if.end.i173
+ unreachable
+
+test1.exit: ; preds = %if.end.i173
+ br i1 undef, label %test1a.exit, label %if.end.i124
+
+if.end.i124: ; preds = %test1.exit
+ unreachable
+
+test1a.exit: ; preds = %test1.exit
+ br i1 undef, label %if.end150, label %for.body137.lr.ph
+
+for.body137.lr.ph: ; preds = %test1a.exit
+ br label %for.body137
+
+for.body137: ; preds = %test1b.exit, %for.body137.lr.ph
+ %ShndxTable.0309 = phi %type1* [ %1, %for.body137.lr.ph ], [ %incdec.ptr, %test1b.exit ]
+ %ret.0..sroa_cast.i.i106 = bitcast %type1* %ShndxTable.0309 to i32*
+ br i1 undef, label %for.body137.if.end146_crit_edge, label %if.then140
+
+for.body137.if.end146_crit_edge: ; preds = %for.body137
+ %incdec.ptr = getelementptr inbounds %type1* %ShndxTable.0309, i64 1
+ br i1 undef, label %cond.false.i70, label %cond.end.i
+
+if.then140: ; preds = %for.body137
+ %ret.0.copyload.i.i102 = load i32* %ret.0..sroa_cast.i.i106, align 2
+
+; CHECK: load {{.*}} align 2
+
+ unreachable
+
+cond.false.i70: ; preds = %for.body137.if.end146_crit_edge
+ unreachable
+
+cond.end.i: ; preds = %for.body137.if.end146_crit_edge
+ br i1 undef, label %test1b.exit, label %cond.false.i.i
+
+cond.false.i.i: ; preds = %cond.end.i
+ unreachable
+
+test1b.exit: ; preds = %cond.end.i
+ br i1 undef, label %if.end150, label %for.body137
+
+if.end150: ; preds = %test1b.exit, %test1a.exit, %if.then126, %if.end123
+ br i1 undef, label %for.end176, label %for.body155.lr.ph
+
+for.body155.lr.ph: ; preds = %if.end150
+ unreachable
+
+for.end176: ; preds = %if.end150
+ unreachable
+
+return: ; preds = %if.end
+ ret void
+}
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind uwtable }
+
More information about the llvm-commits
mailing list