gnu: llvm-9: Backport patch to fix miscompilation for big-endian targets.
* gnu/packages/llvm.scm (llvm-9)[source]: Add new patch. * gnu/packages/patches/llvm-9-fix-bitcast-miscompilation.patch: New file. * gnu/local.mk (dist_patch_DATA): Register new file.
This commit is contained in:
Jakub Kądziołka
parent
7befec258c
commit
ff2f86114c
3 changed files with 194 additions and 0 deletions
|
|
@ -1242,6 +1242,7 @@ dist_patch_DATA = \
|
|||
%D%/packages/patches/lirc-localstatedir.patch \
|
||||
%D%/packages/patches/lirc-reproducible-build.patch \
|
||||
%D%/packages/patches/llvm-3.5-fix-clang-build-with-gcc5.patch \
|
||||
%D%/packages/patches/llvm-9-fix-bitcast-miscompilation.patch \
|
||||
%D%/packages/patches/llvm-9-fix-lpad-miscompilation.patch \
|
||||
%D%/packages/patches/llvm-9-fix-scev-miscompilation.patch \
|
||||
%D%/packages/patches/lm-sensors-hwmon-attrs.patch \
|
||||
|
|
|
|||
|
|
@ -514,6 +514,7 @@ output), and Binutils.")
|
|||
"16hwp3qa54c3a3v7h8nlw0fh5criqh0hlr1skybyk0cz70gyx880"))
|
||||
(patch-flags '("-p2"))
|
||||
(patches (search-patches
|
||||
"llvm-9-fix-bitcast-miscompilation.patch"
|
||||
"llvm-9-fix-scev-miscompilation.patch"
|
||||
"llvm-9-fix-lpad-miscompilation.patch"))))))
|
||||
|
||||
|
|
|
|||
192
gnu/packages/patches/llvm-9-fix-bitcast-miscompilation.patch
Normal file
192
gnu/packages/patches/llvm-9-fix-bitcast-miscompilation.patch
Normal file
|
|
@ -0,0 +1,192 @@
|
|||
From f8e146f3430de3a6cd904f3f3f7aa1bfaefee14c Mon Sep 17 00:00:00 2001
|
||||
From: Bjorn Pettersson <bjorn.a.pettersson@ericsson.com>
|
||||
Date: Thu, 28 Nov 2019 23:18:28 +0100
|
||||
Subject: [PATCH] [InstCombine] Fix big-endian miscompile of (bitcast
|
||||
(zext/trunc (bitcast)))
|
||||
|
||||
Summary:
|
||||
optimizeVectorResize is rewriting patterns like:
|
||||
%1 = bitcast vector %src to integer
|
||||
%2 = trunc/zext %1
|
||||
%dst = bitcast %2 to vector
|
||||
|
||||
Since bitcasting between integer an vector types gives
|
||||
different integer values depending on endianness, we need
|
||||
to take endianness into account. As it happens the old
|
||||
implementation only produced the correct result for little
|
||||
endian targets.
|
||||
|
||||
Fixes: https://bugs.llvm.org/show_bug.cgi?id=44178
|
||||
|
||||
Reviewers: spatel, lattner, lebedev.ri
|
||||
|
||||
Reviewed By: spatel, lebedev.ri
|
||||
|
||||
Subscribers: lebedev.ri, hiraditya, uabelho, llvm-commits
|
||||
|
||||
Tags: #llvm
|
||||
|
||||
Differential Revision: https://reviews.llvm.org/D70844
|
||||
|
||||
(cherry picked from commit a9d6b0e5444741d08ff1df7cf71d1559e7fefc1f)
|
||||
---
|
||||
.../InstCombine/InstCombineCasts.cpp | 79 +++++++++++++------
|
||||
llvm/test/Transforms/InstCombine/cast.ll | 6 +-
|
||||
2 files changed, 60 insertions(+), 25 deletions(-)
|
||||
|
||||
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
|
||||
index 2c9ba203fbf3..0af3de300e77 100644
|
||||
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
|
||||
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
|
||||
@@ -18,6 +18,7 @@
|
||||
#include "llvm/IR/DIBuilder.h"
|
||||
#include "llvm/IR/PatternMatch.h"
|
||||
#include "llvm/Support/KnownBits.h"
|
||||
+#include <numeric>
|
||||
using namespace llvm;
|
||||
using namespace PatternMatch;
|
||||
|
||||
@@ -1820,12 +1821,24 @@ Instruction *InstCombiner::visitPtrToInt(PtrToIntInst &CI) {
|
||||
}
|
||||
|
||||
/// This input value (which is known to have vector type) is being zero extended
|
||||
-/// or truncated to the specified vector type.
|
||||
+/// or truncated to the specified vector type. Since the zext/trunc is done
|
||||
+/// using an integer type, we have a (bitcast(cast(bitcast))) pattern,
|
||||
+/// endianness will impact which end of the vector that is extended or
|
||||
+/// truncated.
|
||||
+///
|
||||
+/// A vector is always stored with index 0 at the lowest address, which
|
||||
+/// corresponds to the most significant bits for a big endian stored integer and
|
||||
+/// the least significant bits for little endian. A trunc/zext of an integer
|
||||
+/// impacts the big end of the integer. Thus, we need to add/remove elements at
|
||||
+/// the front of the vector for big endian targets, and the back of the vector
|
||||
+/// for little endian targets.
|
||||
+///
|
||||
/// Try to replace it with a shuffle (and vector/vector bitcast) if possible.
|
||||
///
|
||||
/// The source and destination vector types may have different element types.
|
||||
-static Instruction *optimizeVectorResize(Value *InVal, VectorType *DestTy,
|
||||
- InstCombiner &IC) {
|
||||
+static Instruction *optimizeVectorResizeWithIntegerBitCasts(Value *InVal,
|
||||
+ VectorType *DestTy,
|
||||
+ InstCombiner &IC) {
|
||||
// We can only do this optimization if the output is a multiple of the input
|
||||
// element size, or the input is a multiple of the output element size.
|
||||
// Convert the input type to have the same element type as the output.
|
||||
@@ -1844,31 +1857,53 @@ static Instruction *optimizeVectorResize(Value *InVal, VectorType *DestTy,
|
||||
InVal = IC.Builder.CreateBitCast(InVal, SrcTy);
|
||||
}
|
||||
|
||||
+ bool IsBigEndian = IC.getDataLayout().isBigEndian();
|
||||
+ unsigned SrcElts = SrcTy->getNumElements();
|
||||
+ unsigned DestElts = DestTy->getNumElements();
|
||||
+
|
||||
+ assert(SrcElts != DestElts && "Element counts should be different.");
|
||||
+
|
||||
// Now that the element types match, get the shuffle mask and RHS of the
|
||||
// shuffle to use, which depends on whether we're increasing or decreasing the
|
||||
// size of the input.
|
||||
- SmallVector<uint32_t, 16> ShuffleMask;
|
||||
+ SmallVector<uint32_t, 16> ShuffleMaskStorage;
|
||||
+ ArrayRef<uint32_t> ShuffleMask;
|
||||
Value *V2;
|
||||
|
||||
- if (SrcTy->getNumElements() > DestTy->getNumElements()) {
|
||||
- // If we're shrinking the number of elements, just shuffle in the low
|
||||
- // elements from the input and use undef as the second shuffle input.
|
||||
- V2 = UndefValue::get(SrcTy);
|
||||
- for (unsigned i = 0, e = DestTy->getNumElements(); i != e; ++i)
|
||||
- ShuffleMask.push_back(i);
|
||||
+ // Produce an identify shuffle mask for the src vector.
|
||||
+ ShuffleMaskStorage.resize(SrcElts);
|
||||
+ std::iota(ShuffleMaskStorage.begin(), ShuffleMaskStorage.end(), 0);
|
||||
|
||||
+ if (SrcElts > DestElts) {
|
||||
+ // If we're shrinking the number of elements (rewriting an integer
|
||||
+ // truncate), just shuffle in the elements corresponding to the least
|
||||
+ // significant bits from the input and use undef as the second shuffle
|
||||
+ // input.
|
||||
+ V2 = UndefValue::get(SrcTy);
|
||||
+ // Make sure the shuffle mask selects the "least significant bits" by
|
||||
+ // keeping elements from back of the src vector for big endian, and from the
|
||||
+ // front for little endian.
|
||||
+ ShuffleMask = ShuffleMaskStorage;
|
||||
+ if (IsBigEndian)
|
||||
+ ShuffleMask = ShuffleMask.take_back(DestElts);
|
||||
+ else
|
||||
+ ShuffleMask = ShuffleMask.take_front(DestElts);
|
||||
} else {
|
||||
- // If we're increasing the number of elements, shuffle in all of the
|
||||
- // elements from InVal and fill the rest of the result elements with zeros
|
||||
- // from a constant zero.
|
||||
+ // If we're increasing the number of elements (rewriting an integer zext),
|
||||
+ // shuffle in all of the elements from InVal. Fill the rest of the result
|
||||
+ // elements with zeros from a constant zero.
|
||||
V2 = Constant::getNullValue(SrcTy);
|
||||
- unsigned SrcElts = SrcTy->getNumElements();
|
||||
- for (unsigned i = 0, e = SrcElts; i != e; ++i)
|
||||
- ShuffleMask.push_back(i);
|
||||
-
|
||||
- // The excess elements reference the first element of the zero input.
|
||||
- for (unsigned i = 0, e = DestTy->getNumElements()-SrcElts; i != e; ++i)
|
||||
- ShuffleMask.push_back(SrcElts);
|
||||
+ // Use first elt from V2 when indicating zero in the shuffle mask.
|
||||
+ uint32_t NullElt = SrcElts;
|
||||
+ // Extend with null values in the "most significant bits" by adding elements
|
||||
+ // in front of the src vector for big endian, and at the back for little
|
||||
+ // endian.
|
||||
+ unsigned DeltaElts = DestElts - SrcElts;
|
||||
+ if (IsBigEndian)
|
||||
+ ShuffleMaskStorage.insert(ShuffleMaskStorage.begin(), DeltaElts, NullElt);
|
||||
+ else
|
||||
+ ShuffleMaskStorage.append(DeltaElts, NullElt);
|
||||
+ ShuffleMask = ShuffleMaskStorage;
|
||||
}
|
||||
|
||||
return new ShuffleVectorInst(InVal, V2,
|
||||
@@ -2359,8 +2394,8 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
|
||||
CastInst *SrcCast = cast<CastInst>(Src);
|
||||
if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0)))
|
||||
if (isa<VectorType>(BCIn->getOperand(0)->getType()))
|
||||
- if (Instruction *I = optimizeVectorResize(BCIn->getOperand(0),
|
||||
- cast<VectorType>(DestTy), *this))
|
||||
+ if (Instruction *I = optimizeVectorResizeWithIntegerBitCasts(
|
||||
+ BCIn->getOperand(0), cast<VectorType>(DestTy), *this))
|
||||
return I;
|
||||
}
|
||||
|
||||
diff --git a/llvm/test/Transforms/InstCombine/cast.ll b/llvm/test/Transforms/InstCombine/cast.ll
|
||||
index b6d1eda0601d..3ce8de033422 100644
|
||||
--- a/llvm/test/Transforms/InstCombine/cast.ll
|
||||
+++ b/llvm/test/Transforms/InstCombine/cast.ll
|
||||
@@ -824,7 +824,7 @@ define i64 @test59(i8 %A, i8 %B) {
|
||||
|
||||
define <3 x i32> @test60(<4 x i32> %call4) {
|
||||
; CHECK-LABEL: @test60(
|
||||
-; CHECK-NEXT: [[P10:%.*]] = shufflevector <4 x i32> [[CALL4:%.*]], <4 x i32> undef, <3 x i32> <i32 0, i32 1, i32 2>
|
||||
+; CHECK-NEXT: [[P10:%.*]] = shufflevector <4 x i32> [[CALL4:%.*]], <4 x i32> undef, <3 x i32> <i32 1, i32 2, i32 3>
|
||||
; CHECK-NEXT: ret <3 x i32> [[P10]]
|
||||
;
|
||||
%p11 = bitcast <4 x i32> %call4 to i128
|
||||
@@ -836,7 +836,7 @@ define <3 x i32> @test60(<4 x i32> %call4) {
|
||||
|
||||
define <4 x i32> @test61(<3 x i32> %call4) {
|
||||
; CHECK-LABEL: @test61(
|
||||
-; CHECK-NEXT: [[P10:%.*]] = shufflevector <3 x i32> [[CALL4:%.*]], <3 x i32> <i32 0, i32 undef, i32 undef>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
|
||||
+; CHECK-NEXT: [[P10:%.*]] = shufflevector <3 x i32> [[CALL4:%.*]], <3 x i32> <i32 0, i32 undef, i32 undef>, <4 x i32> <i32 3, i32 0, i32 1, i32 2>
|
||||
; CHECK-NEXT: ret <4 x i32> [[P10]]
|
||||
;
|
||||
%p11 = bitcast <3 x i32> %call4 to i96
|
||||
@@ -848,7 +848,7 @@ define <4 x i32> @test61(<3 x i32> %call4) {
|
||||
define <4 x i32> @test62(<3 x float> %call4) {
|
||||
; CHECK-LABEL: @test62(
|
||||
; CHECK-NEXT: [[TMP1:%.*]] = bitcast <3 x float> [[CALL4:%.*]] to <3 x i32>
|
||||
-; CHECK-NEXT: [[P10:%.*]] = shufflevector <3 x i32> [[TMP1]], <3 x i32> <i32 0, i32 undef, i32 undef>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
|
||||
+; CHECK-NEXT: [[P10:%.*]] = shufflevector <3 x i32> [[TMP1]], <3 x i32> <i32 0, i32 undef, i32 undef>, <4 x i32> <i32 3, i32 0, i32 1, i32 2>
|
||||
; CHECK-NEXT: ret <4 x i32> [[P10]]
|
||||
;
|
||||
%p11 = bitcast <3 x float> %call4 to i96
|
||||
--
|
||||
2.26.2
|
||||
|
||||
Reference in a new issue