This is a regression present on mainline and 4.7 branch for targets using SJLJ exceptions by default in Ada (e.g. ARM). The error message is:
Unable to coalesce ssa_names 2 and 20 which are marked as MUST COALESCE. b1_2(ab) and b1_20(ab) +===========================GNAT BUG DETECTED==============================+ | 4.8.0 20120716 (experimental) [trunk revision 189525] (x86_64-suse-linux) GCC error:| | SSA corruption | | Error detected around p.adb:4:1 It's the usual case of overlapping live ranges for (ab) SSA names. Tested on x86_64-suse-linux, OK for the mainline and 4.7 branch? 2012-07-18 Eric Botcazou <ebotca...@adacore.com> * tree-ssa-forwprop.c (combine_conversions): Punt if the RHS of the defining statement is a SSA name that occurs in abnormal PHIs. 2012-07-18 Eric Botcazou <ebotca...@adacore.com> * gnat.dg/aggr20.ad[sb]: New test. * gnat.dg/aggr20_pkg.ads: New helper. -- Eric Botcazou
Index: tree-ssa-forwprop.c =================================================================== --- tree-ssa-forwprop.c (revision 189525) +++ tree-ssa-forwprop.c (working copy) @@ -2584,6 +2584,11 @@ combine_conversions (gimple_stmt_iterato unsigned int final_prec = TYPE_PRECISION (type); int final_unsignedp = TYPE_UNSIGNED (type); + /* Don't propagate ssa names that occur in abnormal phis. */ + if (TREE_CODE (defop0) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (defop0)) + return 0; + /* In addition to the cases of two conversions in a row handled below, if we are converting something to its own type via an object of identical or wider precision, neither
-- { dg-do compile } package body Aggr20 is procedure Proc (R : out Rec3) is begin R := (Callback => Nil_Rec2); end; end Aggr20;
with Aggr20_Pkg; use Aggr20_Pkg; with System; package Aggr20 is type Rec1 is record Address : System.Address; end record; Nil_Rec1 : constant Rec1 := (Address => Default_Nil_Address); type Rec2 is record Callback : Rec1; end record; Nil_Rec2 : constant Rec2 := (Callback => Nil_Rec1); type Rec3 is record Callback : Rec2; end record; procedure Proc (R : out Rec3); end Aggr20;
with System; package Aggr20_Pkg is procedure Proc; Default_Nil_Address : constant System.Address := Proc'Address; end Aggr20_Pkg;