diff options
| author | Chris Lattner <sabre@nondot.org> | 2008-02-17 19:43:57 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-02-17 19:43:57 +0000 |
| commit | 1f6520842c2873aff772a39d53582c469b4f399d (patch) | |
| tree | f45ab070a80c27eed9e1108df066751bde5ef82d /llvm/lib/Target | |
| parent | b080ed504e0f617a9532cc37f6c4a853bd5b7996 (diff) | |
| download | bcm5719-llvm-1f6520842c2873aff772a39d53582c469b4f399d.tar.gz bcm5719-llvm-1f6520842c2873aff772a39d53582c469b4f399d.zip | |
move PR2053 to here.
llvm-svn: 47237
Diffstat (limited to 'llvm/lib/Target')
| -rw-r--r-- | llvm/lib/Target/X86/README.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/README.txt b/llvm/lib/Target/X86/README.txt index 846d69403f1..60163e21934 100644 --- a/llvm/lib/Target/X86/README.txt +++ b/llvm/lib/Target/X86/README.txt @@ -1516,3 +1516,15 @@ should generate: lock ; mov %esp, %esp //===---------------------------------------------------------------------===// + +The generated code on x86 for checking for signed overflow on a multiply the +obvious way is much longer than it needs to be. + +int x(int a, int b) { + long long prod = (long long)a*b; + return prod > 0x7FFFFFFF || prod < (-0x7FFFFFFF-1); +} + +See PR2053 for more details. + +//===---------------------------------------------------------------------===// |
