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Remove some stuff that's already implemented. Also, remove the note about

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merging x >u 5 and x <s 20 because it's impossible to implement.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91228 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman 2009-12-12 21:41:48 +00:00
parent 55df144a78
commit 1555473387
1 changed files with 0 additions and 51 deletions
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51
lib/Target/README.txt
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@ -823,20 +823,6 @@ int main() {
//===---------------------------------------------------------------------===//
Instcombine will merge comparisons like (x >= 10) && (x < 20) by producing (x -
10) u< 10, but only when the comparisons have matching sign.
This could be converted with a similiar technique. (PR1941)
define i1 @test(i8 %x) {
%A = icmp uge i8 %x, 5
%B = icmp slt i8 %x, 20
%C = and i1 %A, %B
ret i1 %C
}
//===---------------------------------------------------------------------===//
These functions perform the same computation, but produce different assembly.
define i8 @select(i8 %x) readnone nounwind {
@ -884,18 +870,6 @@ The expression should optimize to something like
//===---------------------------------------------------------------------===//
From GCC Bug 15241:
unsigned int
foo (unsigned int a, unsigned int b)
{
if (a <= 7 && b <= 7)
baz ();
}
Should combine to "(a|b) <= 7". Currently not optimized with "clang
-emit-llvm-bc | opt -std-compile-opts".
//===---------------------------------------------------------------------===//
From GCC Bug 3756:
int
pn (int n)
@ -907,19 +881,6 @@ Should combine to (n >> 31) | 1. Currently not optimized with "clang
//===---------------------------------------------------------------------===//
From GCC Bug 28685:
int test(int a, int b)
{
int lt = a < b;
int eq = a == b;
return (lt || eq);
}
Should combine to "a <= b". Currently not optimized with "clang
-emit-llvm-bc | opt -std-compile-opts | llc".
//===---------------------------------------------------------------------===//
void a(int variable)
{
if (variable == 4 || variable == 6)
@ -993,12 +954,6 @@ Should combine to 0. Currently not optimized with "clang
//===---------------------------------------------------------------------===//
int a(unsigned char* b) {return *b > 99;}
There's an unnecessary zext in the generated code with "clang
-emit-llvm-bc | opt -std-compile-opts".
//===---------------------------------------------------------------------===//
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".
@ -1011,12 +966,6 @@ Should combine to "x | (y & 3)". Currently not optimized with "clang
//===---------------------------------------------------------------------===//
unsigned a(unsigned a) {return ((a | 1) & 3) | (a & -4);}
Should combine to "a | 1". Currently not optimized with "clang
-emit-llvm-bc | opt -std-compile-opts".
//===---------------------------------------------------------------------===//
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".