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[Fix] Non i1 typed select condition for weird pw aff functions.
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  In case the pieceweise affine function used to create an isl_ast_expr
  had empty cases (e.g., with contradicting constraints on the
  parameters), it was possible that the condition of the isl_ast_expr
  select was not a comparison but a constant (thus of type i64).

  This patch does two thing:
   1) Handle the case the condition of a select is not a i1 type like C.
   2) Try to simplify the pieceweise affine functions for the min/max
      access when we generate runtime alias checks. That step can often
      remove empty or redundant cases as well as redundant constrains.

  This fixes bug: http://llvm.org/PR21167

Differential Revision: http://reviews.llvm.org/D5627

llvm-svn: 219208
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Johannes Doerfert committed Oct 7, 2014
1 parent 3cb6372 commit 219b20e
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3 changes: 3 additions & 0 deletions polly/lib/Analysis/ScopInfo.cpp
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Expand Up @@ -1222,6 +1222,9 @@ static int buildMinMaxAccess(__isl_take isl_set *Set, void *User) {
MinPMA = isl_set_lexmin_pw_multi_aff(isl_set_copy(Set));
MaxPMA = isl_set_lexmax_pw_multi_aff(isl_set_copy(Set));

MinPMA = isl_pw_multi_aff_coalesce(MinPMA);
MaxPMA = isl_pw_multi_aff_coalesce(MaxPMA);

// Adjust the last dimension of the maximal access by one as we want to
// enclose the accessed memory region by MinPMA and MaxPMA. The pointer
// we test during code generation might now point after the end of the
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2 changes: 2 additions & 0 deletions polly/lib/CodeGen/IslExprBuilder.cpp
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Expand Up @@ -249,6 +249,8 @@ Value *IslExprBuilder::createOpSelect(__isl_take isl_ast_expr *Expr) {
Type *MaxType = getType(Expr);

Cond = create(isl_ast_expr_get_op_arg(Expr, 0));
if (!Cond->getType()->isIntegerTy(1))
Cond = Builder.CreateIsNotNull(Cond);

LHS = create(isl_ast_expr_get_op_arg(Expr, 1));
RHS = create(isl_ast_expr_get_op_arg(Expr, 2));
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56 changes: 56 additions & 0 deletions polly/test/Isl/CodeGen/test-invalid-operands-for-select-2.ll
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@@ -0,0 +1,56 @@
; RUN: opt %loadPolly -S -polly-code-generator=isl -polly-codegen-isl < %s | FileCheck %s
;
; Check that we do not crash as described here: http://llvm.org/bugs/show_bug.cgi?id=21167
;
; CHECK: polly.split_new_and_old
;
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

; Function Attrs: nounwind uwtable
define void @kernel_fdtd_apml(i32 %cxm, i32 %cym, [65 x [65 x double]]* %Bza, [65 x [65 x double]]* %Hz, double* %czp) #0 {
entry:
br i1 false, label %for.cond4.preheader, label %for.end451

for.cond4.preheader: ; preds = %for.inc449, %entry
%iz.08 = phi i32 [ undef, %for.inc449 ], [ 0, %entry ]
%cmp55 = icmp sgt i32 %cym, 0
br i1 %cmp55, label %for.cond7.preheader, label %for.inc449

for.cond7.preheader: ; preds = %for.end, %for.cond4.preheader
%iy.06 = phi i32 [ %inc447, %for.end ], [ 0, %for.cond4.preheader ]
%cmp81 = icmp sgt i32 %cxm, 0
br i1 %cmp81, label %for.body9, label %for.end

for.body9: ; preds = %for.body9, %for.cond7.preheader
%ix.02 = phi i32 [ %inc, %for.body9 ], [ 0, %for.cond7.preheader ]
%idxprom74 = sext i32 %iz.08 to i64
%arrayidx75 = getelementptr inbounds double* %czp, i64 %idxprom74
%0 = load double* %arrayidx75, align 8
%idxprom102 = sext i32 %iz.08 to i64
%arrayidx105 = getelementptr inbounds [65 x [65 x double]]* %Hz, i64 %idxprom102, i64 0, i64 0
store double undef, double* %arrayidx105, align 8
%inc = add nsw i32 %ix.02, 1
br i1 false, label %for.body9, label %for.end

for.end: ; preds = %for.body9, %for.cond7.preheader
%idxprom209 = sext i32 %cxm to i64
%idxprom211 = sext i32 %iz.08 to i64
%arrayidx214 = getelementptr inbounds [65 x [65 x double]]* %Hz, i64 %idxprom211, i64 0, i64 %idxprom209
store double undef, double* %arrayidx214, align 8
%idxprom430 = sext i32 %cxm to i64
%idxprom431 = sext i32 %cym to i64
%idxprom432 = sext i32 %iz.08 to i64
%arrayidx435 = getelementptr inbounds [65 x [65 x double]]* %Hz, i64 %idxprom432, i64 %idxprom431, i64 %idxprom430
store double undef, double* %arrayidx435, align 8
%arrayidx445 = getelementptr inbounds [65 x [65 x double]]* %Bza, i64 0, i64 0, i64 0
store double undef, double* %arrayidx445, align 8
%inc447 = add nsw i32 %iy.06, 1
%cmp5 = icmp slt i32 %inc447, %cym
br i1 %cmp5, label %for.cond7.preheader, label %for.inc449

for.inc449: ; preds = %for.end, %for.cond4.preheader
br i1 undef, label %for.cond4.preheader, label %for.end451

for.end451: ; preds = %for.inc449, %entry
ret void
}
81 changes: 81 additions & 0 deletions polly/test/Isl/CodeGen/test-invalid-operands-for-select.ll
View file
@@ -0,0 +1,81 @@
; RUN: opt %loadPolly -S -polly-code-generator=isl -polly-codegen-isl -polly-codegen-scev < %s | FileCheck %s
;
; Check that we do not crash as described here: http://llvm.org/PR21167
;
; In case the pieceweise affine function used to create an isl_ast_expr
; had empty cases (e.g., with contradicting constraints on the
; parameters), it was possible that the condition of the isl_ast_expr
; select was not a comparison but a constant (thus of type i64).
; However, we shouldn't crash in such a case :)
;
; CHECK: polly.split_new_and_old
;
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

; Function Attrs: nounwind uwtable
define void @dradb4(i32 %ido, i32 %l1, float* %cc, float* %ch, float* %wa1, float* %wa3) #0 {
entry:
%mul = mul nsw i32 %l1, %ido
br i1 undef, label %for.end256, label %if.end

if.end: ; preds = %entry
br i1 undef, label %L105, label %for.cond45.preheader

for.cond45.preheader: ; preds = %if.end
br i1 undef, label %for.body47, label %for.end198

for.body47: ; preds = %for.inc196, %for.cond45.preheader
br i1 undef, label %for.body53.lr.ph, label %for.inc196

for.body53.lr.ph: ; preds = %for.body47
br label %for.body53

for.body53: ; preds = %for.body53, %for.body53.lr.ph
%t7.014 = phi i32 [ 0, %for.body53.lr.ph ], [ %add58, %for.body53 ]
%i.013 = phi i32 [ 2, %for.body53.lr.ph ], [ %add193, %for.body53 ]
%add58 = add nsw i32 %t7.014, 2
%arrayidx70 = getelementptr inbounds float* %cc, i64 0
%arrayidx72 = getelementptr inbounds float* %cc, i64 0
%arrayidx77 = getelementptr inbounds float* %cc, i64 0
%arrayidx81 = getelementptr inbounds float* %cc, i64 0
%arrayidx84 = getelementptr inbounds float* %cc, i64 0
%arrayidx95 = getelementptr inbounds float* %cc, i64 0
%arrayidx105 = getelementptr inbounds float* %cc, i64 0
%arrayidx110 = getelementptr inbounds float* %ch, i64 0
store float undef, float* %arrayidx110, align 4
%arrayidx122 = getelementptr inbounds float* %wa1, i64 0
%add129 = add nsw i32 %add58, %mul
%idxprom142 = sext i32 %add129 to i64
%arrayidx143 = getelementptr inbounds float* %ch, i64 %idxprom142
store float undef, float* %arrayidx143, align 4
%add153 = add nsw i32 %add129, %mul
%arrayidx170 = getelementptr inbounds float* %wa3, i64 0
%arrayidx174 = getelementptr inbounds float* %wa3, i64 0
%add177 = add nsw i32 %add153, %mul
%sub178 = add nsw i32 %add177, -1
%idxprom179 = sext i32 %sub178 to i64
%arrayidx180 = getelementptr inbounds float* %ch, i64 %idxprom179
store float undef, float* %arrayidx180, align 4
%arrayidx183 = getelementptr inbounds float* %wa3, i64 0
%0 = load float* %arrayidx183, align 4
%mul184 = fmul float undef, %0
%add189 = fadd float %mul184, 0.000000e+00
%idxprom190 = sext i32 %add177 to i64
%arrayidx191 = getelementptr inbounds float* %ch, i64 %idxprom190
store float %add189, float* %arrayidx191, align 4
%add193 = add nsw i32 %i.013, 2
%cmp52 = icmp slt i32 %add193, %ido
br i1 %cmp52, label %for.body53, label %for.inc196

for.inc196: ; preds = %for.body53, %for.body47
br i1 undef, label %for.body47, label %for.end198

for.end198: ; preds = %for.inc196, %for.cond45.preheader
br i1 false, label %for.end256, label %L105

L105: ; preds = %for.end198, %if.end
br label %for.end256

for.end256: ; preds = %L105, %for.end198, %entry
ret void
}

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