diff options
| -rw-r--r-- | lib/Support/APInt.cpp | 2 | ||||
| -rw-r--r-- | lib/Target/X86/README.txt | 10 | ||||
| -rw-r--r-- | test/CodeGen/X86/divide-by-constant.ll | 2 | ||||
| -rw-r--r-- | unittests/ADT/APIntTest.cpp | 18 |
4 files changed, 24 insertions, 8 deletions
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp index 77033428b5..08f36d2af3 100644 --- a/lib/Support/APInt.cpp +++ b/lib/Support/APInt.cpp @@ -1505,7 +1505,7 @@ APInt::ms APInt::magic() const { r2 = r2 - ad; } delta = ad - r2; - } while (q1.ule(delta) || (q1 == delta && r1 == 0)); + } while (q1.ult(delta) || (q1 == delta && r1 == 0)); mag.m = q2 + 1; if (d.isNegative()) mag.m = -mag.m; // resulting magic number diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index c10e1709f6..ed3bff150b 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -1888,12 +1888,10 @@ Compiles to: $clang t.c -S -o - -O3 -mkernel -fomit-frame-pointer _t: ## @t movslq %edi, %rax - imulq $-1431655765, %rax, %rcx ## imm = 0xFFFFFFFFAAAAAAAB - shrq $32, %rcx - addl %ecx, %eax - movl %eax, %ecx - shrl $31, %ecx - shrl %eax + imulq $1431655766, %rax, %rax ## imm = 0x55555556 + movq %rax, %rcx + shrq $63, %rcx + shrq $32, %rax addl %ecx, %eax movsbl %al, %eax ret diff --git a/test/CodeGen/X86/divide-by-constant.ll b/test/CodeGen/X86/divide-by-constant.ll index 7ceb972f61..fe335b9369 100644 --- a/test/CodeGen/X86/divide-by-constant.ll +++ b/test/CodeGen/X86/divide-by-constant.ll @@ -40,7 +40,7 @@ entry: %div = sdiv i16 %x, 33 ; <i32> [#uses=1] ret i16 %div ; CHECK: test4: -; CHECK: imull $-1985, %ecx, %ecx +; CHECK: imull $1986, %eax, %eax } define i32 @test5(i32 %A) nounwind { diff --git a/unittests/ADT/APIntTest.cpp b/unittests/ADT/APIntTest.cpp index 557d835bac..e05bdbfc71 100644 --- a/unittests/ADT/APIntTest.cpp +++ b/unittests/ADT/APIntTest.cpp @@ -332,6 +332,24 @@ TEST(APIntTest, Log2) { EXPECT_EQ(APInt(15, 9).exactLogBase2(), -1); } +TEST(APIntTest, magic) { + EXPECT_EQ(APInt(32, 3).magic().m, APInt(32, "55555556", 16)); + EXPECT_EQ(APInt(32, 3).magic().s, 0U); + EXPECT_EQ(APInt(32, 5).magic().m, APInt(32, "66666667", 16)); + EXPECT_EQ(APInt(32, 5).magic().s, 1U); + EXPECT_EQ(APInt(32, 7).magic().m, APInt(32, "92492493", 16)); + EXPECT_EQ(APInt(32, 7).magic().s, 2U); +} + +TEST(APIntTest, magicu) { + EXPECT_EQ(APInt(32, 3).magicu().m, APInt(32, "AAAAAAAB", 16)); + EXPECT_EQ(APInt(32, 3).magicu().s, 1U); + EXPECT_EQ(APInt(32, 5).magicu().m, APInt(32, "CCCCCCCD", 16)); + EXPECT_EQ(APInt(32, 5).magicu().s, 2U); + EXPECT_EQ(APInt(32, 7).magicu().m, APInt(32, "24924925", 16)); + EXPECT_EQ(APInt(32, 7).magicu().s, 3U); +} + #ifdef GTEST_HAS_DEATH_TEST #ifndef NDEBUG TEST(APIntTest, StringDeath) { |