something that reassoc doesn't think about yet.
-//===---------------------------------------------------------------------===//
-
-This function: (derived from GCC PR19988)
-double foo(double x, double y) {
- return ((x + 0.1234 * y) * (x + -0.1234 * y));
-}
-
-compiles to:
-_foo:
- movapd %xmm1, %xmm2
- mulsd LCPI1_1(%rip), %xmm1
- mulsd LCPI1_0(%rip), %xmm2
- addsd %xmm0, %xmm1
- addsd %xmm0, %xmm2
- movapd %xmm1, %xmm0
- mulsd %xmm2, %xmm0
- ret
-
-Reassociate should be able to turn it into:
-
-double foo(double x, double y) {
- return ((x + 0.1234 * y) * (x - 0.1234 * y));
-}
-
-Which allows the multiply by constant to be CSE'd, producing:
-
-_foo:
- mulsd LCPI1_0(%rip), %xmm1
- movapd %xmm1, %xmm2
- addsd %xmm0, %xmm2
- subsd %xmm1, %xmm0
- mulsd %xmm2, %xmm0
- ret
-
-This doesn't need -ffast-math support at all. This is particularly bad because
-the llvm-gcc frontend is canonicalizing the later into the former, but clang
-doesn't have this problem.
-
//===---------------------------------------------------------------------===//
These two functions should generate the same code on big-endian systems:
return ((a & (c - 1)) != 0) | ((b & (c - 1)) != 0);
}
Both should combine to ((a|b) & (c-1)) != 0. Currently not optimized with
-"clang -emit-llvm-bc | opt -std-compile-opts".
+"clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
}
The expression should optimize to something like
"!((start|end)&~PMD_MASK). Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
return (abs(x)) >= 0;
}
This should optimize to x == INT_MIN. (With -fwrapv.) Currently not
-optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
All should simplify to a single comparison. All of these are
currently not optimized with "clang -emit-llvm-bc | opt
--std-compile-opts".
+-O3".
//===---------------------------------------------------------------------===//
From GCC Bug 32605:
int c(int* x) {return (char*)x+2 == (char*)x;}
Should combine to 0. Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts" (although llc can optimize it).
+-emit-llvm-bc | opt -O3" (although llc can optimize it).
//===---------------------------------------------------------------------===//
int a(unsigned b) {return ((b << 31) | (b << 30)) >> 31;}
Should be combined to "((b >> 1) | b) & 1". Currently not optimized
-with "clang -emit-llvm-bc | opt -std-compile-opts".
+with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
unsigned a(unsigned x, unsigned y) { return x | (y & 1) | (y & 2);}
Should combine to "x | (y & 3)". Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int a, int b, int c) {return (~a & c) | ((c|a) & b);}
Should fold to "(~a & c) | (a & b)". Currently not optimized with
-"clang -emit-llvm-bc | opt -std-compile-opts".
+"clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int a,int b) {return (~(a|b))|a;}
Should fold to "a|~b". Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int a, int b) {return (a&&b) || (a&&!b);}
Should fold to "a". Currently not optimized with "clang -emit-llvm-bc
-| opt -std-compile-opts".
+| opt -O3".
//===---------------------------------------------------------------------===//
int a(int a, int b, int c) {return (a&&b) || (!a&&c);}
Should fold to "a ? b : c", or at least something sane. Currently not
-optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int a, int b, int c) {return (a&&b) || (a&&c) || (a&&b&&c);}
Should fold to a && (b || c). Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int x) {return x | ((x & 8) ^ 8);}
Should combine to x | 8. Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int x) {return x ^ ((x & 8) ^ 8);}
Should also combine to x | 8. Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int a(int x) {return ((x | -9) ^ 8) & x;}
Should combine to x & -9. Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
unsigned a(unsigned a) {return a * 0x11111111 >> 28 & 1;}
Should combine to "a * 0x88888888 >> 31". Currently not optimized
-with "clang -emit-llvm-bc | opt -std-compile-opts".
+with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
unsigned a(char* x) {if ((*x & 32) == 0) return b();}
There's an unnecessary zext in the generated code with "clang
--emit-llvm-bc | opt -std-compile-opts".
+-emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
unsigned a(unsigned long long x) {return 40 * (x >> 1);}
Should combine to "20 * (((unsigned)x) & -2)". Currently not
-optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int g(int x) { return (x - 10) < 0; }
Should combine to "x <= 9" (the sub has nsw). Currently not
-optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int g(int x) { return (x + 10) < 0; }
Should combine to "x < -10" (the add has nsw). Currently not
-optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
int f(int i, int j) { return i < j + 1; }
int g(int i, int j) { return j > i - 1; }
Should combine to "i <= j" (the add/sub has nsw). Currently not
-optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
unsigned f(unsigned x) { return ((x & 7) + 1) & 15; }
The & 15 part should be optimized away, it doesn't change the result. Currently
-not optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+not optimized with "clang -emit-llvm-bc | opt -O3".
//===---------------------------------------------------------------------===//
GCC testsuite, ones we don't get yet are (checked through loadpre25):
[CRIT EDGE BREAKING]
-loadpre3.c predcom-4.c
+predcom-4.c
[PRE OF READONLY CALL]
loadpre5.c
..
else if (strchr ("<>", *intel_parser.op_string)
-Those should be turned into a switch.
+Those should be turned into a switch. SimplifyLibCalls only gets the second
+case.
//===---------------------------------------------------------------------===//
//===---------------------------------------------------------------------===//
-This code (from Benchmarks/Dhrystone/dry.c):
-
-define i32 @Func1(i32, i32) nounwind readnone optsize ssp {
-entry:
- %sext = shl i32 %0, 24
- %conv = ashr i32 %sext, 24
- %sext6 = shl i32 %1, 24
- %conv4 = ashr i32 %sext6, 24
- %cmp = icmp eq i32 %conv, %conv4
- %. = select i1 %cmp, i32 10000, i32 0
- ret i32 %.
-}
-
-Should be simplified into something like:
-
-define i32 @Func1(i32, i32) nounwind readnone optsize ssp {
-entry:
- %sext = shl i32 %0, 24
- %conv = and i32 %sext, 0xFF000000
- %sext6 = shl i32 %1, 24
- %conv4 = and i32 %sext6, 0xFF000000
- %cmp = icmp eq i32 %conv, %conv4
- %. = select i1 %cmp, i32 10000, i32 0
- ret i32 %.
-}
-
-and then to:
-
-define i32 @Func1(i32, i32) nounwind readnone optsize ssp {
-entry:
- %conv = and i32 %0, 0xFF
- %conv4 = and i32 %1, 0xFF
- %cmp = icmp eq i32 %conv, %conv4
- %. = select i1 %cmp, i32 10000, i32 0
- ret i32 %.
-}
-//===---------------------------------------------------------------------===//
-
clang -O3 currently compiles this code
int g(unsigned int a) {
projects / oota-llvm.git / blobdiff