gnu/packages/patches/llvm-9-fix-scev-miscompilation.patch

   1 Guix note: this got detected with the test suite of rustc 1.41.1, but
   2 the issue potentially affects all consumers of LLVM.
   3
   4 From 58e8c793d0e43150a6452e971a32d7407a8a7401 Mon Sep 17 00:00:00 2001
   5 From: Tim Northover <tnorthover@apple.com>
   6 Date: Mon, 30 Sep 2019 07:46:52 +0000
   7 Subject: [PATCH] Revert "[SCEV] add no wrap flag for SCEVAddExpr."
   8
   9 This reverts r366419 because the analysis performed is within the context of
  10 the loop and it's only valid to add wrapping flags to "global" expressions if
  11 they're always correct.
  12
  13 llvm-svn: 373184
  14 ---
  15  llvm/lib/Analysis/ScalarEvolution.cpp              | 2 +-
  16  llvm/test/Analysis/ScalarEvolution/limit-depth.ll  | 2 +-
  17  llvm/test/Analysis/ScalarEvolution/nsw.ll          | 2 +-
  18  llvm/test/Analysis/ScalarEvolution/trip-count12.ll | 2 +-
  19  llvm/test/Analysis/ScalarEvolution/trip-count9.ll  | 8 ++++----
  20  5 files changed, 8 insertions(+), 8 deletions(-)
  21
  22 diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
  23 index 354ae05bb841..c29fc5dbccfb 100644
  24 --- llvm/lib/Analysis/ScalarEvolution.cpp
  25 +++ llvm/lib/Analysis/ScalarEvolution.cpp
  26 @@ -4992,7 +4992,7 @@ const SCEV *ScalarEvolution::createSimpleAffineAddRec(PHINode *PN,
  27    // overflow.
  28    if (auto *BEInst = dyn_cast<Instruction>(BEValueV))
  29      if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L))
  30 -      (void)getAddRecExpr(getAddExpr(StartVal, Accum, Flags), Accum, L, Flags);
  31 +      (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags);
  32
  33    return PHISCEV;
  34  }
  35 diff --git a/llvm/test/Analysis/ScalarEvolution/limit-depth.ll b/llvm/test/Analysis/ScalarEvolution/limit-depth.ll
  36 index db68a4f84c91..6fdf8c5df974 100644
  37 --- llvm/test/Analysis/ScalarEvolution/limit-depth.ll
  38 +++ llvm/test/Analysis/ScalarEvolution/limit-depth.ll
  39 @@ -46,7 +46,7 @@ define void @test_mul(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f) {
  40  define void @test_sext(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f) {
  41  ; CHECK-LABEL: @test_sext
  42  ; CHECK:        %se2 = sext i64 %iv2.inc to i128
  43 -; CHECK-NEXT:   -->  {(1 + (sext i64 {(sext i32 (1 + %a)<nsw> to i64),+,1}<nsw><%loop> to i128))<nsw>,+,1}<nsw><%loop2>
  44 +; CHECK-NEXT:   -->  {(1 + (sext i64 {(sext i32 (1 + %a) to i64),+,1}<nsw><%loop> to i128))<nsw>,+,1}<nsw><%loop2>
  45  entry:
  46    br label %loop
  47
  48 diff --git a/llvm/test/Analysis/ScalarEvolution/nsw.ll b/llvm/test/Analysis/ScalarEvolution/nsw.ll
  49 index 69427368625d..ca24f9d4a04b 100644
  50 --- llvm/test/Analysis/ScalarEvolution/nsw.ll
  51 +++ llvm/test/Analysis/ScalarEvolution/nsw.ll
  52 @@ -163,7 +163,7 @@ bb5:                                              ; preds = %bb2
  53  declare void @f(i32)
  54
  55  ; CHECK-LABEL: nswnowrap
  56 -; CHECK: --> {(1 + %v)<nsw>,+,1}<nsw><%for.body>{{ U: [^ ]+ S: [^ ]+}}{{ *}}Exits: (2 + %v)
  57 +; CHECK: --> {(1 + %v)<nsw>,+,1}<nsw><%for.body>{{ U: [^ ]+ S: [^ ]+}}{{ *}}Exits: (1 + ((1 + %v)<nsw> smax %v))
  58  define void @nswnowrap(i32 %v, i32* %buf) {
  59  entry:
  60    %add = add nsw i32 %v, 1
  61 diff --git a/llvm/test/Analysis/ScalarEvolution/trip-count12.ll b/llvm/test/Analysis/ScalarEvolution/trip-count12.ll
  62 index 5e7d72d5e4f3..d0086ee2e6ac 100644
  63 --- llvm/test/Analysis/ScalarEvolution/trip-count12.ll
  64 +++ llvm/test/Analysis/ScalarEvolution/trip-count12.ll
  65 @@ -1,7 +1,7 @@
  66  ; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
  67
  68  ; CHECK: Determining loop execution counts for: @test
  69 -; CHECK: Loop %for.body: backedge-taken count is ((-2 + %len)<nsw> /u 2)
  70 +; CHECK: Loop %for.body: backedge-taken count is ((-2 + %len) /u 2)
  71  ; CHECK: Loop %for.body: max backedge-taken count is 1073741823
  72
  73  define zeroext i16 @test(i16* nocapture %p, i32 %len) nounwind readonly {
  74 diff --git a/llvm/test/Analysis/ScalarEvolution/trip-count9.ll b/llvm/test/Analysis/ScalarEvolution/trip-count9.ll
  75 index c0a1d12fa00e..9a080b34743f 100644
  76 --- llvm/test/Analysis/ScalarEvolution/trip-count9.ll
  77 +++ llvm/test/Analysis/ScalarEvolution/trip-count9.ll
  78 @@ -179,7 +179,7 @@ exit:
  79  }
  80
  81  ; CHECK: Determining loop execution counts for: @nsw_startx
  82 -; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x)<nsw> smax %n))
  83 +; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x) smax %n))
  84  ; CHECK: Loop %loop: max backedge-taken count is -1
  85  define void @nsw_startx(i4 %n, i4 %x) {
  86  entry:
  87 @@ -195,7 +195,7 @@ exit:
  88  }
  89
  90  ; CHECK: Determining loop execution counts for: @nsw_startx_step2
  91 -; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x)<nsw> smax %n)) /u 2)
  92 +; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x) smax %n)) /u 2)
  93  ; CHECK: Loop %loop: max backedge-taken count is 7
  94  define void @nsw_startx_step2(i4 %n, i4 %x) {
  95  entry:
  96 @@ -381,7 +381,7 @@ exit:
  97  }
  98
  99  ; CHECK: Determining loop execution counts for: @even_nsw_startx
 100 -; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x)<nsw> smax (2 * %n)))
 101 +; CHECK: Loop %loop: backedge-taken count is (-1 + (-1 * %x) + ((1 + %x) smax (2 * %n)))
 102  ; CHECK: Loop %loop: max backedge-taken count is -2
 103  define void @even_nsw_startx(i4 %n, i4 %x) {
 104  entry:
 105 @@ -398,7 +398,7 @@ exit:
 106  }
 107
 108  ; CHECK: Determining loop execution counts for: @even_nsw_startx_step2
 109 -; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x)<nsw> smax (2 * %n))) /u 2)
 110 +; CHECK: Loop %loop: backedge-taken count is ((-1 + (-1 * %x) + ((2 + %x) smax (2 * %n))) /u 2)
 111  ; CHECK: Loop %loop: max backedge-taken count is 7
 112  define void @even_nsw_startx_step2(i4 %n, i4 %x) {
 113  entry: