[PATCH] D43363: [APInt] Fix extractBits to correctly handle Result.isSingleWord() case.
Tim Shen via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 15 17:04:29 PST 2018
timshen created this revision.
timshen added a reviewer: RKSimon.
Herald added subscribers: hiraditya, sanjoy.
extractBits assumes that `!this->isSingleWord() implies !Result.isSingleWord()`, which may not necessarily be true. Handle both cases.
https://reviews.llvm.org/D43363
Files:
llvm/lib/Support/APInt.cpp
llvm/unittests/ADT/APIntTest.cpp
Index: llvm/unittests/ADT/APIntTest.cpp
===================================================================
--- llvm/unittests/ADT/APIntTest.cpp
+++ llvm/unittests/ADT/APIntTest.cpp
@@ -1768,6 +1768,13 @@
i257.extractBits(128, 1).getSExtValue());
EXPECT_EQ(static_cast<int64_t>(0xFFFFFFFFFF80007Full),
i257.extractBits(129, 1).getSExtValue());
+
+ EXPECT_EQ(APInt(48, 0),
+ APInt(144, "281474976710655", 10).extractBits(48, 48));
+ EXPECT_EQ(APInt(48, 0x0000ffffffffffffull),
+ APInt(144, "281474976710655", 10).extractBits(48, 0));
+ EXPECT_EQ(APInt(48, 0x00007fffffffffffull),
+ APInt(144, "281474976710655", 10).extractBits(48, 1));
}
TEST(APIntTest, getLowBitsSet) {
Index: llvm/lib/Support/APInt.cpp
===================================================================
--- llvm/lib/Support/APInt.cpp
+++ llvm/lib/Support/APInt.cpp
@@ -428,11 +428,12 @@
unsigned NumSrcWords = getNumWords();
unsigned NumDstWords = Result.getNumWords();
+ uint64_t *DestPtr = Result.isSingleWord() ? &Result.U.VAL : Result.U.pVal;
for (unsigned word = 0; word < NumDstWords; ++word) {
uint64_t w0 = U.pVal[loWord + word];
uint64_t w1 =
(loWord + word + 1) < NumSrcWords ? U.pVal[loWord + word + 1] : 0;
- Result.U.pVal[word] = (w0 >> loBit) | (w1 << (APINT_BITS_PER_WORD - loBit));
+ DestPtr[word] = (w0 >> loBit) | (w1 << (APINT_BITS_PER_WORD - loBit));
}
return Result.clearUnusedBits();
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